Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 11,011	$ 9,168
Net unrealized holding gain (loss) on securities available for sale	7,455	(2,939)
Reclassification adjustments for net gain recognized in income	(6)	(2)
Tax effect	(3,026)	1,173
Net unrealized gain (loss) on securities available for sale, net of tax	4,423	(1,768)
Amortization of net actuarial (gain) loss	(72)	132
Amortization of prior service credit	(45)	(66)
Tax effect	45	(25)
Amortization of net actuarial loss and prior service credit on pension and postretirement plans, net of tax	(72)	41
Other comprehensive income (loss), net of tax	4,351	(1,727)
Comprehensive income	$ 15,362	$ 7,441