Income Taxes - Provision for Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal									$ 345,204	$ 269,047	$ 181,403
State and local									32,393	31,155	37,655
Foreign									(6,183)	2,038	517
Total current income tax provision									371,414	302,240	219,575
Deferred:
Federal									(31,731)	694	84,504
State and local									5,611	85	5,742
Foreign									(1,903)	(1,976)	(2,198)
Total deferred income tax (benefit) provision									(28,023)	(1,197)	88,048
Provision for income taxes	$ 76,706	$ 75,110	$ 120,326	$ 71,249	$ 55,868	$ 75,910	$ 92,359	$ 76,906	$ 343,391	$ 301,043	$ 307,623