Subsequent Events (Details) (USD $) In Thousands, except Share data in Millions, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended		55 Months Ended
	Nov. 09, 2012	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012
Subsequent Event
Treasury Stock, Shares, Acquired	0.5	0.7	1.1
Payments for Repurchase of Common Stock			$ 14,472	$ 28,875
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities	75		31,300		176,100
Repurchase of Equity [Member]
Subsequent Event
Treasury Stock, Shares, Acquired	0.5
Payments for Repurchase of Common Stock	$ 6,200