Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income tax provision	$ 60,822,000	$ 46,250,000	$ 170,135,000	$ 115,418,000
Effective income tax rate, percent	36.80%	35.30%	36.60%	35.10%
Effective income tax rate, at federal statutory income tax rate, percent	35.00%	35.00%	35.00%	35.00%
Cash paid for taxes, net of refunds received			$ 110,800,000	$ 45,700,000