Income Taxes Provision (benefit) for income taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Current Federal Income Tax Expense	$ 77,400,000	$ 13,200,000	$ 6,200,000
Current State and Foreign Tax Expense (Benefit)	3,700,000	2,800,000	(600,000)
Current Income Tax Expense	81,100,000	16,000,000	5,600,000
Deferred Federal Income Tax Expense (Benefit)	(12,200,000)	11,400,000	(12,800,000)
Deferred State Income Tax Expense (Benefit)	(1,700,000)	2,400,000	(2,100,000)
Deferred Income Tax Expense (Benefit)	(13,900,000)	13,800,000	(14,900,000)
Income Tax Expense (Benefit)	$ 67,249,000	$ 29,806,000	$ (9,292,000)