Securities (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012
Rollforward of the credit losses recognized in earnings
Beginning balance	$ 15,167	$ 15,180	$ 15,070	$ 14,983
Increases to the amount related to the credit loss for which other-than-temporary impairment was previously recognized	13	11	110
Amounts realized for securities sold during the period		(208)
Ending balance	$ 15,180	$ 14,983	$ 15,180	$ 14,983