Supplemental Cash Flows Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Supplemental disclosure of cash flow data:
Interest paid	$ 31,289	$ 37,819
Income taxes paid	14,842	5,672
Supplemental disclosure of non-cash investing and financing activities:
Contingent consideration and acquisition holdback payable	1,337	6,400
Contingent consideration settled with the issuance of Class A common stock		$ 771
Exchange of Class C and Class D common stock for Class A common stock	$ (20,985)