Annual report pursuant to Section 13 and 15(d)

Derivative Instruments and Hedging Activities - Effects on statements of income and consolidated statements of comprehensive income (Details)

v3.6.0.2
Derivative Instruments and Hedging Activities - Effects on statements of income and consolidated statements of comprehensive income (Details) - Interest Rate Swap - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Designated as Hedging Instrument        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain Recognized in Net Income (Loss) $ (279) $ (368) $ (1,418)  
Not Designated as Hedging Instrument        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain Recognized in Net Income (Loss)       $ (266)