Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended				9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Benefit Plans	Dec. 31, 2012 Benefit Plans	Sep. 30, 2013 Unrealized Gains and Losses on Securities Available for Sale	Sep. 30, 2013 Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period			$ 376		$ (7,458)	$ (7,458)	$ 8,764	$ (930)
Other comprehensive income (loss) before reclassifications			(11,146)				(11,285)	139
Amounts reclassified from accumulated other comprehensive income			142					142
Other comprehensive income (loss), net of tax	(1,037)	1,532	(11,004)	2,521			(11,285)	281
Balance at the end of the period	$ (10,628)	$ (228)	$ (10,628)	$ (228)	$ (7,458)	$ (7,458)	$ (2,521)	$ (649)