ARS Call and Redemption, Settlement of the Put Right and UBS Credit Facility Repayment (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Auction rate securities, called at par		$ 37,200,000
Auction rate securities, put to UBS		61,700,000
UBS Put Right		0
Write off of UBS Put Right		11,700,000
Auction rate securities, impact on income statement	0	26,000	500,000
UBS Credit Facility [Member]
Line of credit facility, amount outstanding		0
Auction Rate Securities [Member]
Marketable Securities, Fixed Maturities		0
Gain (Loss) on Investments		$ 11,700,000