Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Class A common stock	Class B common stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Total
Balance at beginning of the period at Dec. 31, 2014	$ 198	$ 316		$ 136,896	$ (24,118)	$ 85	$ 61,008	$ 174,385
Balance at beginning of the period (in shares) at Dec. 31, 2014	19,770,893	31,621,542
Changes in Equity
Net income (loss)					22,557		58,889	81,446
Equity-based compensation	$ 1			30,479			2,857	33,337
Equity-based compensation (in shares)	84,841	(5,412)
Other comprehensive income (loss)						(19)	2	(17)
Dividends and distributions				2,732	(16,792)		(50,334)	(64,394)
Treasury Stock purchases			$ (7,006)					$ (7,006)
Treasury Stock purchases (in shares)			(242,619)					(242,619)
Class A Partnership Units and other equity purchased or converted into Class A Common Stock	$ 5	$ (2)		5,112			(727)	$ 4,388
Class A Partnership Units and other equity purchased or converted into Class A Common Stock (in shares)	545,115	(257,401)
Net excess tax benefit (detriment) from equity-based compensation				435				435
Balance at end of the period at Sep. 30, 2015	$ 204	$ 314	$ (7,006)	175,654	(18,353)	66	71,695	222,574
Balance at end of the period (in shares) at Sep. 30, 2015	20,400,849	31,358,729	(242,619)
Balance at beginning of the period at Dec. 31, 2015	$ 205	$ 312	$ (7,616)	190,703	(15,338)	108	89,044	257,418
Balance at beginning of the period (in shares) at Dec. 31, 2015	20,536,740	31,229,236	(263,622)
Changes in Equity
Net income (loss)					23,352		63,785	87,137
Equity-based compensation	$ 3			53,934			2,376	56,313
Equity-based compensation (in shares)	253,757	(2,132)
Other comprehensive income (loss)						(552)	(921)	(1,473)
Dividends and distributions				10,276	(45,610)		(100,417)	(135,751)
Treasury Stock purchases			$ (2,621)					$ (2,621)
Treasury Stock purchases (in shares)			(98,126)					(98,126)
Class A Partnership Units and other equity purchased or converted into Class A Common Stock	$ 1	$ (1)		900			(117)	$ 783
Class A Partnership Units and other equity purchased or converted into Class A Common Stock (in shares)	103,538	(88,911)
Net excess tax benefit (detriment) from equity-based compensation				(48)				(48)
Other				766				766
Balance at end of the period at Sep. 30, 2016	$ 209	$ 311	$ (10,237)	$ 256,531	$ (37,596)	$ (444)	$ 53,750	$ 262,524
Balance at end of the period (in shares) at Sep. 30, 2016	20,894,035	31,138,193	(361,748)