Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Components of Income Tax Expense

Income tax expense included in net income consisted of the following components:

	Years Ended December 31,
(in thousands)	2015			2014			2013
Included in net income
Current federal	$	17,378		$	41,441		$	14,797
Current state		4,241			1,487			(3,207	)
Total current provision		21,619			42,928			11,590
Deferred federal		15,457			21,483			37,403
Deferred state		1,228			2,054			3,517
Total deferred provision		16,685			23,537			40,920
Total included in net income	$	38,304		$	66,465		$	52,510
Included in shareholders’ equity
Deferred tax related to retirement benefits		(11,532	)	$	(14,681	)	$	32,749
Deferred tax related to securities		(6,762	)		6,857			(40,876	)
Deferred tax related to derivatives and hedging		114			(217	)		116
Total included in shareholders’ equity	$	(18,180	)	$	(8,041	)	$	(8,011	)

Components of the Company's Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities were as follows:

	December 31,
(in thousands)	2015			2014
Deferred tax assets:
Allowance for loan losses	$	72,940		$	57,667
Employee compensation and benefits		26,853			50,361
Loan purchase accounting adjustments		18,977			35,094
Tax credit carryforward		42,850			35,553
Securities		5,038			—
State net operating loss		1,910			1,535
Other		10,928			8,472
Gross deferred tax assets		179,496			188,682
State valuation allowance		(1,910	)		(1,529	)
Subtotal valuation allowance		(1,910	)		(1,529	)
Net deferred tax assets		177,586			187,153
Deferred tax liabilities:
Fixed assets & intangibles		(80,389	)		(88,062	)
Securities		—			(724	)
FDIC indemnification asset		(10,688	)		(18,769	)
Other		(10,679	)		(5,263	)
Gross deferred tax liabilities		(101,756	)		(112,818	)
Net deferred tax asset	$	75,830		$	74,335

Schedule of Effective Income Tax Rate Reconciliation

A summary of the factors that impacted income tax expense follows:

	Years Ended December 31,
	2015						2014						2013
($ in thousands)	Amount			%			Amount			%			Amount			%
Taxes computed at statutory rate	$	59,418			35	%	$	84,766			35	%	$	75,553			35	%
Increases (decreases) in taxes resulting from:
State income taxes, net of federal income tax benefit		2,595			2			4,649			2			2,352			1
Tax-exempt interest		(7,849	)		(5	)		(6,301	)		(3	)		(6,487	)		(3	)
Bank owned life insurance		(3,798	)		(2	)		(3,554	)		(1	)		(3,926	)		(2	)
Tax credits		(12,495	)		(7	)		(16,577	)		(7	)		(15,743	)		(7	)
Other, net		433			—			3,482			1			761			—
Income tax expense	$	38,304			23	%	$	66,465			27	%	$	52,510			24	%