Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Derivative Financial Instruments (Details)

v3.8.0.1
Summary of Significant Accounting Policies - Derivative Financial Instruments (Details) - Interest rate swap instruments
$ in Thousands
 1 Months Ended 3 Months Ended 12 Months Ended
Feb. 28, 2018
USD ($)
Jun. 30, 2017
USD ($)
Sep. 30, 2015
USD ($)
Oct. 31, 2012
USD ($)
swap
Jul. 31, 2011
USD ($)
Mar. 31, 2010
USD ($)
Jun. 30, 2014
USD ($)
Dec. 31, 2013
USD ($)
Sep. 30, 2013
USD ($)
Dec. 31, 2007
USD ($)
contract
Derivative [Line Items]                    
Number of instruments held | contract                   2
Amount of (gain) loss recognized in earnings on derivative               $ (266)    
Interest expense reclassified from accumulated other comprehensive income (loss)             $ 566      
Interest Rate Swap Contract 1                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps                   $ 13,081
Interest rate swaps, variable to fixed interest rates                   5.40%
Interest Rate Swap Contract 2                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps                   $ 3,256
Interest rate swaps, variable to fixed interest rates                   5.30%
Interest Rate Swap Contract 3                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps           $ 27,900        
Interest rate swaps, variable to fixed interest rates           3.74%        
Term of interest rate swap contract           14 years        
Interest Rate Swap Contract 4                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps         $ 38,571          
Interest rate swaps, variable to fixed interest rates         1.965%          
Term of interest rate swap contract         5 years          
Interest Rate Swap Contract 5                    
Derivative [Line Items]                    
Number of instruments held | swap       2            
Initial notional amount of interest rate swaps       $ 16,750            
Interest rate swaps, variable to fixed interest rates       1.71%            
Term of interest rate swap contract       8 years            
Future increase in notional amount                 $ 42,247  
Interest Rate Swap Contract 6                    
Derivative [Line Items]                    
Number of instruments held | swap       2            
Initial notional amount of interest rate swaps       $ 25,377            
Interest rate swaps, variable to fixed interest rates       3.70%            
Term of interest rate swap contract       8 years            
Interest Rate Swap Contract 7                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps     $ 20,746              
Interest rate swaps, variable to fixed interest rates     2.19%              
Term of interest rate swap contract     7 years              
Interest Rate Swap Contract 8                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps     $ 14,084              
Interest rate swaps, variable to fixed interest rates     3.26%              
Term of interest rate swap contract     15 years              
Interest Rate Swap Contract 9                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps   $ 14,100                
Interest rate swaps, variable to fixed interest rates   2.29%                
Term of interest rate swap contract   10 years                
Interest Rate Swap Contract 10 | Not Designated as Hedging Instrument                    
Derivative [Line Items]                    
Initial notional amount of interest rate swaps $ 17,100                  
Interest rate swaps, variable to fixed interest rates 2.45%                  
Term of interest rate swap contract 3 years