Acquisitions - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Consolidated net (loss) income	$ (600)	$ (2,697)	$ (51,270)	$ (1,376)	$ (19,343)	$ (118)	$ 1,824	$ 1,920	$ (55,943)	$ (15,717)	$ 38,802
Revenue from services											916,149
Net income attributable to common shareholders											$ 40,255
Net income per common share attributable to common shareholders - basic (usd per share)											$ 1.16
Net income per common share attributable to common shareholders - diluted (usd per share)											$ 1.09
Acquisition-related costs
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Consolidated net (loss) income											$ 2,000