Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 111,556	$ 106,310	$ 108,242	$ 112,543			$ 214,552	$ 326,108	$ 296,893
Effective income tax rate (as a percent)	36.50%			40.30%				37.60%	44.20%
Increase in valuation allowance						$ 44,392
Increase in deferred tax asset					$ 14,831
Valuation allowance	$ 49,257							$ 49,257		$ 49,095