Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 156,937	$ 181,640	$ 146,633
State	34,927	36,281	33,054
Foreign	20,725	13,892	15,377
Deferred:
Federal and state	(3,785)	(8,398)	(4,626)
Foreign	1,917	(181)	983
Provision (benefit) for income taxes	$ 210,721	$ 223,234	$ 191,421