Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	May 13, 2011
Condensed Financial Statements, Captions [Line Items]
Allowance for doubtful accounts	$ 4,133	$ 4,691
Debt issuance costs/ discounts	$ 27,914	$ 29,909
Interest rate	7.75%	7.75%
Treasury stock, shares	2,806,187	2,806,187
Class A common stock
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	93,750,000	93,750,000
Common stock, shares issued	32,031,952	32,031,952
Common stock, shares outstanding	29,225,765	29,225,765
Class C common stock
Condensed Financial Statements, Captions [Line Items]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	80,609	80,609
Common stock, shares issued	80,609	80,609
Common stock, shares outstanding	80,609	80,609
7.75% senior notes:
Condensed Financial Statements, Captions [Line Items]
Interest rate	7.75%	7.75%	7.75%
Debt issuance costs	$ 5,591	$ 6,200