Business Acquisition - (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 03, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisitions
Total revenues		$ 205,739	$ 205,427	$ 562,481	$ 517,613
Net income (loss)		(1,477)	$ 11,897	1,609	$ 130,049
Savvy
Business Acquisitions
Acquisition price	$ 42,968
Total revenues		18,400		35,800
Net income (loss)		$ (1,300)		$ (1,500)