Income Taxes - Federal Tax purpose (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
	Mar. 31, 2018	Oct. 06, 2016	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
U.S. Federal income tax rate (as a percent)			21.00%	35.00%	35.00%
Deferred tax expense					$ 118,400
Effective tax rate			29.50%	10.10%
Uncertain tax positions	$ 0		$ 0		0
Interest or penalties relating to income taxes			0		0
Current portion of liabilities under tax receivable agreement	$ 8,093		$ 8,093		$ 8,093
Tax receivable agreement
Expected future tax benefits retained by the Company (as a percent)		15.00%
Tax receivable agreement | Continuing Equity Owners and Crestview partners II GP LP
Payment, as percent of tax benefits (as a percent)		85.00%
CWGS, LLC | Tax receivable agreement
Units issued in exchange			173,286	10,000
CWH | CWGS, LLC
Ownership interest	41.70%	22.60%	41.70%		41.50%
Units held	36,930,269		36,930,269		36,749,072
Crestview Partners II GP LP | Tax receivable agreement
Liability under tax receivable agreement	$ 139,500		$ 139,500		$ 137,700
Current portion of liabilities under tax receivable agreement	$ 8,100		$ 8,100		$ 8,100