Condensed Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 30, 2016 - USD ($) $ in Thousands	Additional paid-in capital	Common Stock Class A common stock	Common Stock Class B common stock	Retained earnings Class A common stock	Retained earnings	Accumulated other comprehensive (loss), net of tax	Non-controlling interest	Class A common stock	Class B common stock	Total
Beginning balance, Value at Dec. 31, 2015	$ 445,081	$ 2			$ 4,693	$ (105)	$ (410,257)			$ 39,414
Beginning balance, Shares at Dec. 31, 2015		17,584,351	1
Net income					11,901		12,875			24,776
Distributions paid and payable to non-controlling unitholders							(8,912)			(8,912)
Equity-based compensation expense	1,311									1,311
Dividends to Class A common stockholders				$ 5,285				$ 5,285
Change in accumulated other comprehensive income (loss)						263	301			564
Issuance of Class A common stock, equity-based compensation plans	101									101
Issuance of Class A common stock, equity-based compensation plans, shares		71,745
Payroll taxes related to net settled restricted stock units	(360)									(360)
Payroll taxes related to net settled restricted stock units (in shares)		(10,400)
Ending balance, Value at Jun. 30, 2016	446,256	$ 2			11,265	$ 158	(406,044)			51,637
Ending balance, Shares at Jun. 30, 2016		17,645,696	1					17,584,351	1
Cumulative effect adjustment from change in accounting principle	$ 123				$ (44)		$ (51)			$ 28