Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Intangible Assets - Additional Information (Details)

v3.10.0.1
Goodwill and Intangible Assets - Additional Information (Details)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
project
Sep. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Finite-Lived Intangible Assets [Line Items]          
Number of projects acquired | project     2    
Goodwill acquired during the year     $ 3,042    
Gross Carrying Amount $ 26,393   26,393   $ 25,998
Accumulated Amortization 24,078   24,078   23,558
Intangible assets, net 2,315   2,315   2,440
Amortization of intangible assets     771 $ 1,082  
Customer contracts          
Finite-Lived Intangible Assets [Line Items]          
Gross Carrying Amount 7,888   7,888   7,786
Accumulated Amortization 7,708   7,708   7,786
Amortization of intangible assets 0 $ 8 0 23  
Customer relationships          
Finite-Lived Intangible Assets [Line Items]          
Gross Carrying Amount 12,195   12,195   11,863
Accumulated Amortization 10,151   10,151   9,557
Non-compete agreements          
Finite-Lived Intangible Assets [Line Items]          
Gross Carrying Amount 3,029   3,029   3,052
Accumulated Amortization 3,028   3,028   3,048
Technology          
Finite-Lived Intangible Assets [Line Items]          
Gross Carrying Amount 2,737   2,737   2,751
Accumulated Amortization 2,665   2,665   2,642
Trade names          
Finite-Lived Intangible Assets [Line Items]          
Gross Carrying Amount 544   544   546
Accumulated Amortization 526   526   $ 525
Other intangible assets          
Finite-Lived Intangible Assets [Line Items]          
Amortization of intangible assets $ 269 $ 358 771 $ 1,059  
Undisclosed Name of Acquiree 1 | Customer relationships          
Finite-Lived Intangible Assets [Line Items]          
Finite-lived intangible assets acquired     $ 500    
Remaining amortization period of asset acquired     8 years    
Undisclosed Name of Acquiree 2 | Customer contracts          
Finite-Lived Intangible Assets [Line Items]          
Finite-lived intangible assets acquired     $ 180    
Remaining amortization period of asset acquired     2 years    
Minimum          
Finite-Lived Intangible Assets [Line Items]          
All other acquired intangible assets useful life     1 year    
Minimum | Customer contracts          
Finite-Lived Intangible Assets [Line Items]          
Acquired intangible assets useful life     1 year    
Minimum | Other intangible assets          
Finite-Lived Intangible Assets [Line Items]          
All other acquired intangible assets useful life     4 years    
Maximum          
Finite-Lived Intangible Assets [Line Items]          
All other acquired intangible assets useful life     15 years    
Maximum | Customer contracts          
Finite-Lived Intangible Assets [Line Items]          
Acquired intangible assets useful life     5 years    
Maximum | Other intangible assets          
Finite-Lived Intangible Assets [Line Items]          
All other acquired intangible assets useful life     15 years