Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Effective tax rate on income before income taxes	(1.40%)	2.10%	(1.50%)	1.80%
Net deferred tax asset	$ 66,700,000		$ 66,700,000		$ 66,000,000
Income taxes paid, net of recoveries			9,600,000	4,100,000
Federal excise taxes incurred	$ 2,300,000	$ 2,800,000	$ 7,300,000	$ 8,700,000