Income Taxes - Provision for income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal									$ 904	$ 279	$ 2,358
State and local									(1,441)	(3,072)	(8,769)
Total current income tax provision									(537)	(2,793)	(6,411)
Deferred federal									35,573	(26,005)	6,402
Deferred other									3,694	(3,957)	(102)
Total deferred income tax provision									39,267	(29,962)	6,300
Provision (benefit) for income taxes	$ 22,978	$ 9,615	$ 6,932	$ (795)	$ (17,094)	$ (4,099)	$ (6,539)	$ (5,023)	$ 38,730	$ (32,755)	$ (111)