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, 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)					13,863		37,961	51,824
Equity-based compensation	$ 3			37,070			1,633	38,706
Equity-based compensation (in shares)	250,042	(1,774)
Other comprehensive income (loss)						(248)	(409)	(657)
Dividends declared and distributions				7,774	(36,483)		(89,201)	(117,910)
Treasury Stock purchases			$ (2,609)					$ (2,609)
Treasury Stock purchases (in shares)			(97,601)					(97,601)
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				(47)				(47)
Other				132				132
Balance at end of the period at Jun. 30, 2016	$ 209	$ 311	$ (10,225)	236,532	(37,958)	(140)	38,911	227,640
Balance at end of the period (in shares) at Jun. 30, 2016	20,890,320	31,138,551	(361,223)
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
Balance at beginning of the period at Dec. 31, 2016	$ 210	$ 311	$ (10,930)	291,026	(68,229)	(543)	39,596	251,441
Balance at beginning of the period (in shares) at Dec. 31, 2016	20,948,998	31,138,193	(387,890)
Changes in Equity
Net income (loss)					35,008		53,895	88,903
Equity-based compensation	$ 16			48,514			1,199	49,729
Equity-based compensation (in shares)	1,554,754
Other comprehensive income (loss)						617	665	1,282
Dividends declared and distributions				17,176	(64,872)		(95,442)	(143,138)
Treasury Stock purchases			$ (9,266)					$ (9,266)
Treasury Stock purchases (in shares)			(250,550)					(250,550)
Class A Partnership Units and other equity purchased or converted into Class A Common Stock	$ 3	$ (1)		6,685			(14)	$ 6,673
Class A Partnership Units and other equity purchased or converted into Class A Common Stock (in shares)	297,755	(54,678)
Issuance of Class A common stock and cancellation of Class B common stock in connection with offering	$ 53	$ (53)		28,374			(6,294)	22,080
Issuance of Class A common stock and cancellation of Class B common stock in connection with offering (in shares)	5,356,876	(5,356,876)
Equity-based payments to non-employees				2,914				2,914
Other				(36)				(36)
Balance at end of the period at Jun. 30, 2017	$ 282	$ 257	$ (20,196)	$ 399,508	$ (102,290)	$ 74	$ (6,395)	$ 271,240
Balance at end of the period (in shares) at Jun. 30, 2017	28,158,383	25,726,639	(638,440)