Accumulated Other Comprehensive Income Reclassifications out of Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	$ 236	$ 236	$ 259	$ 2,089
Total, net of tax	(2,792)	3,183	(4,069)	7,779
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total, net of tax	(445)	(363)	(445)	(1,955)
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 on Derivatives [Line Items]
Net realized gains on sale of securities	(720)	(345)	(720)	(2,723)
Income tax expense	275	136	275	1,076
Total, net of tax	(445)	(209)	(445)	(1,647)
Defined benefit plan items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Personnel expense	0	(255)	0	(509)
Income tax expense	0	101	0	201
Total, net of tax	$ 0	$ (154)	$ 0	$ (308)