Statement of Changes in Stockholders' Equity - 6 months ended Jun. 30, 2017 - USD ($) shares in Thousands, $ in Thousands	Common Stock Class A common stock	Common Stock Class B common stock	Treasury Stock Class A common stock	Additional Paid-in-Capital	Retained (Deficit)/ Earnings	Non-controlling Interest	Class A common stock	Total
Balance at Dec. 31, 2016	$ 57	$ 30	$ (358)	$ 447,137	$ (8,652)	$ 453,237		$ 891,451
Balance (in shares) at Dec. 31, 2016	57,025	29,832	23
Increase (Decrease) Stockholders' Equity
Cumulative effect of adoption of ASU 2016-09				706	(706)
Stock-compensation expense	$ 1			3,273				3,274
Stock-compensation expense (in shares)	756
Cash tax distribution						(562)		(562)
Sale of common stock	$ 4			8,348				8,352
Sale of common stock (in shares)	3,716						3,700
Stock dividends on common stock	$ 5			17,495	(17,500)
Stock dividends on common stock (in shares)	5,000
Exchange of Class B Shares for Class A Shares				118		(123)		(5)
Exchange of Class B shares for Class A shares (in shares)	8	(8)
Dividends and accretion on preferred stock				313	(3,993)			(3,680)
Dividends and accretion on preferred stock (in shares)	144
Net income (loss)					(90,626)	(58,221)		(148,847)
Balance at Jun. 30, 2017	$ 67	$ 30	$ (358)	$ 477,390	$ (121,477)	$ 394,331		$ 749,983
Balance (in shares) at Jun. 30, 2017	66,649	29,824	23