Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net income	$ 15,307	$ 17,271
Other comprehensive income:
Increase in net unrealized gains on securities available for sale	7,823	1,272
Deferred tax expense	(3,289)	(534)
Increase in net unrealized gains on securities available for sale, net of tax	4,534	738
Post-retirement benefit transition obligation amortization	15	15
Deferred tax expense	(6)	(6)
Post-retirement benefit transition obligation amortization, net of tax	9	9
Total other comprehensive income	4,543	747
Total comprehensive income	$ 19,850	$ 18,018