Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit)

The components of the provision for income taxes are as follows:

	2011			2010		2009
	(in thousands)
Current tax expense (benefit):
Federal	$	40,141		$	38,333	$	36,162
State	6,319			532		(322		)
	46,460			38,865		35,840
Deferred tax expense (benefit):
Federal	8,662			5,544		(20,432		)
State	(4,284		)	—		—
	4,378			5,544		(20,432		)
Income tax expense	$	50,838		$	44,409	$	15,408

Schedule of Effective Income Tax Rate Reconciliation

The differences between the effective income tax rate and the federal statutory income tax rate are as follows:

	2011		2010		2009
Statutory tax rate	35.0	%	35.0	%	35.0	%
Effect of tax-exempt income	(5.3	)	(5.8	)	(11.2	)
Effect of low income housing investments	(4.3	)	(3.3	)	(5.3	)
Bank-owned life insurance	(0.6	)	(0.6	)	(1.2	)
State income taxes, net of Federal benefit	(4.0	)	—		(0.7	)
Valuation allowance	4.6		0.2		0.5
Other, net	0.5		0.2		0.1
Effective income tax rate	25.9	%	25.7	%	17.2	%

Schedule of Deferred Tax Assets and Liabilities

The net deferred tax asset recorded by the Corporation is included in other assets and consists of the following tax effects of temporary differences as of December 31:

	2011			2010
	(in thousands)
Deferred tax assets:
Allowance for credit losses	$	95,788		$	96,408
Other-than-temporary impairment of investments	15,490			17,482
State loss carryforwards	12,405			8,232
Postretirement and defined benefit plans	11,527			5,588
Other accrued expenses	10,415			13,075
Deferred compensation	9,568			9,553
Other	16,262			7,476
Total gross deferred tax assets	171,455			157,814
Deferred tax liabilities:
Unrealized holding gains on securities available for sale	14,025			10,769
Mortgage servicing rights	11,776			10,745
Direct leasing	7,561			5,048
Premises and equipment	6,919			7,557
Acquisition premiums/discounts	6,174			5,069
Other	5,885			7,358
Total gross deferred tax liabilities	52,340			46,546
Net deferred tax asset before valuation allowance	119,115			111,268
Valuation allowance	(17,321		)	(8,232		)
Net deferred tax asset	$	101,794		$	103,036

Summary of Income Tax Contingencies

The following summarizes the changes in unrecognized tax benefits (in thousands):

	2011			2010
	(in thousands)
Balance at beginning of year	$	4,083		$	4,481
Prior period tax positions	4,492			—
Current period tax positions	1,958			582
Lapse of statute of limitations	(1,095		)	(980		)
Balance at end of year	$	9,438		$	4,083