Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits, net of interest and penalties	$ 1,500,000		$ 1,500,000		$ 1,300,000
Tax benefit of intraperiod tax allocation	0	0	4,200,000	0
Amount of valuation allowance released	0	0	0	0
Total income tax payments, net of refunds	1,366,000	1,843,000	3,981,000	13,029,000
Less: credits or offsets	491,000	842,000	1,915,000	4,340,000
Cash paid, net	$ 875,000	$ 1,001,000	$ 2,066,000	$ 8,689,000