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)					6,970		18,649	25,619
Other comprehensive income (loss)						(25)	(41)	(66)
Equity-based compensation	$ 2			15,794			897	16,693
Equity-based compensation (in shares)	186,516	(1,640)
Dividends declared and distributions				5,351	(27,882)		(70,313)	(92,844)
Treasury Stock purchases			$ (1,847)					$ (1,847)
Treasury Stock purchases (in shares)			(70,431)					(70,431)
Net excess tax benefit from equity-based compensation				(89)				$ (89)
Other				34				34
Balance at end of the period at Mar. 31, 2016	$ 207	$ 312	$ (9,463)	211,793	(36,250)	83	38,236	204,918
Balance at end of the period (in shares) at Mar. 31, 2016	20,723,256	31,227,596	(334,053)
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
Treasury Stock purchases								(1,847)
Balance at end of the period (Prior to Adjustment, ASU 2016-09) at Dec. 31, 2016	$ 210	$ 311	$ (10,930)	291,026	(68,229)	(543)	39,596	251,441
Balance at end of the period (Adjusted, ASU 2016-09) at Dec. 31, 2016	$ 210	$ 311	$ (10,930)	295,881	(72,426)	(543)	39,596	252,099
Balance at end of the period at Dec. 31, 2016								251,441
Balance at end of the period (in shares) (Prior to Adjustment, ASU 2016-09) at Dec. 31, 2016	20,948,998	31,138,193	(387,890)
Balance at end of the period (in shares) (Adjusted, ASU 2016-09) at Dec. 31, 2016	20,948,998	31,138,193	(387,890)
Changes in Equity
Cumulative Effect Adjustment upon Adoption of ASU | ASU 2016-09				4,855	(4,197)			658
Net income (loss)					15,278		24,101	39,379
Other comprehensive income (loss)						246	278	524
Equity-based compensation	$ 9			25,206			688	25,903
Equity-based compensation (in shares)	886,818
Equity-based payments to non-employees				1,874				1,874
Dividends declared and distributions				3,706	(13,606)		(51,188)	(61,088)
Treasury Stock purchases			$ (7,534)					$ (7,534)
Treasury Stock purchases (in shares)			(205,085)					(205,085)
Issuance of Class A common stock and acquisition of Class B common stock in connection with follow-on offering	$ 53	$ (53)		28,374			(6,294)	$ 22,080
Issuance of Class A common stock and acquisition of Class B common stock in connection with follow-on offering (in shares)	5,356,876	(5,356,876)
Other				(36)				(36)
Balance at end of the period at Mar. 31, 2017	$ 272	$ 258	$ (18,464)	$ 355,005	$ (70,754)	$ (297)	$ 7,181	$ 273,201
Balance at end of the period (in shares) at Mar. 31, 2017	27,192,692	25,781,317	(592,975)