Accumulated Other Comprehensive Income (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	$ (1,468)		$ 1,249		$ (10,112)		$ 1,505
Unrealized gain (loss) on securities, net of tax	(2,322)		1,874		(14,548)		2,258
Change in funded status of post retirement benefits	566		645		1,486		1,932
Income tax expense	(226)		(258)		(594)		(773)
Net of tax	340		377		888		760
Amount Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net securities gains (losses)	0		17		7		666
Income tax expense	0		(7)		(3)		(267)
Unrealized gain (loss) on securities, net of tax	0		10		4		399
Change in funded status of post retirement benefits	(566)	[1]	(645)	[1]	(1,486)	[1]	(1,932)	[1]
Income tax expense	226		258		594		773
Net of tax	(340)		(387)		(892)		(1,159)
Net of tax	$ (340)		$ (377)		$ (888)		$ (760)

[1] Included in the computation of net periodic benefit cost. (see Footnote 7 for additional details).