Income Taxes (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Income tax expense	$ 34,784	$ 20,121	$ 155,283	$ 70,989
Effective tax rate	37.00%	36.00%	38.00%	37.00%
Federal statutory rate			35.00%	35.00%
State income tax expense	1,083	1,147	7,792	4,210
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	11,204		11,237	1,544
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	1,784	(570)	4,172	(2,370)
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	22,000		22,000
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			4,920
Second component of tax deductible goodwill, net of tax			1,210
Tax Adjustments, Settlements, and Unusual Provisions			$ 447