Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Expense (Benefit)	$ 26,414,000	$ 28,724,000	$ 58,933,000	$ 55,060,000
Effective Income Tax Rate, Continuing Operations			39.00%	38.30%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	29,400,000		29,400,000		26,700,000
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations			156,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	500,000	200,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 4,300,000		$ 4,300,000		$ 3,200,000