CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 9,960		$ 8,900		$ 26,364		$ 26,051
Securities available for sale:
Changes in fair value in securities available for sale	(129)		(218)		(5,003)		(676)
Net losses (gains) on securities reclassified into earnings	0	[1]	0	[1]	393	[1]	(138)	[1]
Net change in fair value of securities available for sale	(129)		(218)		(4,610)		(814)
Reclassification adjustment for other-than-temporary impairment losses transferred into earnings	0	[2]	0	[2]	1,384	[2]	80	[2]
Cash flow hedges:
Change in fair value of cash flow hedges	(47)		(127)		(15)		(331)
Net cash flow hedge losses reclassified into earnings	91	[3]	113	[3]	331	[3]	336	[3]
Net change in fair value of cash flow hedges	44		(14)		316		5
Defined benefit plan obligation adjustment	11,440	[4]	171	[4]	12,069	[4]	527	[4]
Total other comprehensive (loss) income, net of tax	11,355		(61)		9,159		(202)
Total comprehensive income	$ 21,315		$ 8,839		$ 35,523		$ 25,849

[1] Reported as total other-than-temporary impairment losses on securities in the Consolidated Statement of Income.

[2] Reported as the portion of loss recognized in other comprehensive income in the Consolidated Statement of Income.

[3] Included in interest expense on junior subordinated debentures in the Consolidated Statement of Income.

[4] Included in salaries and employee benefits expense in the Consolidated Statement of Income. See Note 12 and the Annual Report on Form 10-K for fiscal year 2012 for additional information.