Deferred Tax Assets and Deferred Tax Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets
Allowance for loan and lease losses	$ 50,652	$ 50,963
Other real estate owned	8,041	7,685
Deferred compensation	4,837	3,129
Employee benefits	3,132	2,715
Federal income tax credits	2,778	3,543
Interest rate swap agreements	0	6,549
Other	7,813	7,835
Total gross deferred tax assets	77,253	82,419
Deferred tax liabilities
FHLB stock dividends	(10,359)	(10,143)
Deferred loan costs	(6,058)	(5,316)
Available-for-sale securities	(5,402)	(37,083)
Depreciation of premises and equipment	(3,939)	(5,437)
Intangibles	(3,099)	(1,117)
Interest rate swap agreements	(736)	0
Other	(4,111)	(2,929)
Total gross deferred tax liabilities	(33,704)	(62,025)
Net deferred tax asset	$ 43,549	$ 20,394