CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 10,310	$ 7,561	$ 45,122	$ 25,252	$ 6,909
Other comprehensive income (loss) net of tax:
Unrealized holding gain (loss) on securities available for sale arising during the period, net of tax of $654, $10,658, and $106			1,214	19,793	(197)
Unrealized loss on securities transferred to held-to-maturity, net of tax of $2,864				(5,315)
Unrealized gain (loss) on securities available for sale for which a portion of an other than temporary impairment has been recognized in income, net of tax of $56, $86, and $539			(104)	160	(1,001)
Reclassification adjustment for net gains included in net income net of tax of $759, $714, and $652			(952)	(2,129)	288
Defined Benefit Pension Plans, net of tax of $346, $2,492, and $526			(1,413)	(1,326)	(1,210)
Net Gain (Loss) Arising During Period			(577)	(5,722)	156
Prior Service Cost Arising During Period				26	583
Amortization of Prior Service Cost			(65)	1,068	50
Other Comprehensive Income, net of tax			(1,897)	6,555	(1,331)
Comprehensive income			43,225	31,807	5,578
Components of accumulated other comprehensive income (loss)
Net unrealized gain on securities available for sale	17,904	18,244	17,904	18,244
Net unrealized loss on securities available for sale for which a portion of an other-than-temporary impairment has been recognized in income	(3,272)	(3,168)	(3,272)	(3,168)
Net unrealized loss on cash flow hedges	(2,652)	(1,841)	(2,652)	(1,841)
Defined benefit plans	(17,479)	(16,837)	(17,479)	(16,837)
Accumulated other comprehensive loss	$ (5,499)	$ (3,602)	$ (5,499)	$ (3,602)