Quarterly report pursuant to Section 13 or 15(d)

Acquisitions - Chieftain Acquisition Narrative (Details)

v3.10.0.1
Acquisitions - Chieftain Acquisition Narrative (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Business Acquisition [Line Items]      
Cash paid to acquire a business $ 13,356 $ 39,570  
Chieftain Acquisition      
Business Acquisition [Line Items]      
Transaction related costs expensed     $ 800