ARS Call and Redemption, Settlement of the Put Right and UBS Credit Facility Repayment (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
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	0	26,000
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