Consolidated Statements of Changes in Equity - 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)					33,104		87,113	120,217
Equity-based compensation	$ 1			42,400			3,730	46,131
Equity-based compensation (in shares)	134,228	(5,412)
Other comprehensive income (loss)						23	76	99
Dividends declared and distributions				4,130	(24,324)		(60,715)	(80,909)
Treasury Stock purchases			$ (7,616)					(7,616)
Treasury Stock purchases (in shares)			(263,622)
Class A Partnership Units and other equity purchased or converted to Class A Common Stock	$ 6	$ (4)		5,727			(1,093)	4,636
Class A Partnership Units and other equity purchased or converted to Class A Common Stock (in shares)	631,619	(343,857)
Net excess tax benefit (detriment) from equity-based compensation				428				428
Other				1,122			(1,075)	47
Other (in shares)		(43,037)
Balance at end of the period at Dec. 31, 2015	$ 205	$ 312	$ (7,616)	190,703	(15,338)	108	89,044	257,418
Balance at end of the period (in shares) at Dec. 31, 2015	20,536,740	31,229,236	(263,622)
Changes in Equity
Net income (loss)					38,387		103,478	141,865
Equity-based compensation	$ 4			73,914			3,132	77,050
Equity-based compensation (in shares)	308,720	(2,132)
Other comprehensive income (loss)						(651)	(1,083)	(1,734)
Dividends declared and distributions				23,367	(91,278)		(154,858)	(222,769)
Treasury Stock purchases			$ (3,314)					$ (3,314)
Treasury Stock purchases (in shares)			(124,268)					(124,268)
Class A Partnership Units and other equity purchased or converted to Class A Common Stock	$ 1	$ (1)		952			(117)	$ 835
Class A Partnership Units and other equity purchased or converted to Class A Common Stock (in shares)	103,538	(88,911)
Net excess tax benefit (detriment) from equity-based compensation				(62)				(62)
Other				2,152				2,152
Balance at end of the period at Dec. 31, 2016	$ 210	$ 311	$ (10,930)	291,026	(68,229)	(543)	39,596	251,441
Balance at end of the period (in shares) at Dec. 31, 2016	20,948,998	31,138,193	(387,890)
Changes in Equity
Cumulative Effect Adjustment upon Adoption of ASU 2016-09				4,855	(4,197)			658
Balance at beginning of the period, as adjusted	$ 210	$ 311	$ (10,930)	295,881	(72,426)	(543)	39,596	252,099
Net income (loss)					29,400		97,124	126,524
Equity-based compensation	$ 17			94,141			2,137	96,295
Equity-based compensation (in shares)	1,708,826
Other comprehensive income (loss)						895	932	1,827
Dividends declared and distributions				24,657	(96,892)		(115,393)	(187,628)
Treasury Stock purchases			$ (12,258)					$ (12,258)
Treasury Stock purchases (in shares)			(319,526)					(319,526)
Exercise of stock options	$ 3			6,052				$ 6,055
Exercise of stock options (in shares)	279,277
Issuance of Class A common stock and cancellation of Class B common stock in connection with offerings and other exchanges	$ 112	$ (112)		60,762			(5,090)	55,672
Issuance of Class A common stock and cancellation of Class B common stock in connection with offerings and other exchanges (in shares)	11,226,067	(11,225,963)
Equity-based payments to non-employees				5,615				5,615
Other				55				55
Other (in shares)	(126)
Balance at end of the period at Dec. 31, 2017	$ 342	$ 199	$ (23,188)	$ 487,163	$ (139,918)	$ 352	$ 19,306	$ 344,256
Balance at end of the period (in shares) at Dec. 31, 2017	34,163,042	19,912,230	(707,416)