Accumulated Other Comprehensive Income Reclassifications out of Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit (expense)	$ (1,853)	$ 77
Total, net of tax	(4,596)	(10,859)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total, net of tax	(1,592)
Unrealized gains (losses) on available for sale securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains on sale of securities	(2,377)
Income tax benefit (expense)	939
Total, net of tax	(1,438)
Defined benefit plan items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Personnel expense	(254)
Income tax benefit (expense)	100
Total, net of tax	$ (154)