Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Schedule of Provision for Income Tax Expense

The provision for income tax expense consists of the following for the years ended December 31:

(Dollars in thousands)	2015			2014			2013
Current expense	$	67,025		$	69,612		$	62,468
Deferred expense (benefit)	4,551			(25,027		)	(35,930		)
Tax credits	(11,268		)	(12,012		)	(11,690		)
ASU 2014-01 Amortization on Low Income Housing Tax Credits	2,023			1,005			251
Tax benefits attributable to items charged to equity and goodwill	1,763			2,105			1,034
	$	64,094		$	35,683		$	16,133

Reconciliation of Effective Tax Rate

The provision for federal income taxes differs from the amount computed by applying the federal income tax statutory rate of 35 percent on income before income tax expense as indicated in the following analysis for the years ended December 31:

(Dollars in thousands)	2015			2014			2013
Federal tax based on statutory rate	$	72,428		$	49,373		$	28,441
Increase (decrease) resulting from:
Effect of tax-exempt income	(6,919		)	(7,064		)	(7,282		)
Interest and other nondeductible expenses	5,899			2,642			2,007
State taxes, net of federal benefit	3,955			2,531			3,237
Tax credits	(11,268		)	(12,012		)	(11,690		)
ASU 2014-01 Amortization on Low Income Housing Tax Credits	2,023			1,005			251
Other	(2,024		)	(792		)	1,169
	$	64,094		$	35,683		$	16,133
Effective tax rate	31.0		%	25.3		%	19.9		%

Deferred Tax Assets and Liabilities

The net deferred tax asset at December 31 is as follows:

(Dollars in thousands)	2015			2014
Deferred tax asset:
NOL carryforward	$	17,258		$	978
Allowance for credit losses	56,446			59,267
Deferred compensation	7,528			6,631
Basis difference in acquired assets	48,256			53,202
Unrealized loss on securities available for sale	854			—
OREO	6,210			9,845
Other	10,438			13,530
	146,990			143,453
Deferred tax liability:
Basis difference in acquired assets	(31,975		)	(53,940		)
Gain on acquisition	(212		)	(2,426		)
FHLB stock	(122		)	(85		)
Premises and equipment	(1,658		)	(9,652		)
Acquisition intangibles	(7,648		)	(12,151		)
Deferred loan costs	(4,610		)	(3,771		)
Unrealized gain on securities available for sale	—			(4,052		)
Investments acquired	(167		)	(570		)
Swap gain	—			(75		)
Other	(16,694		)	(12,908		)
	(63,086		)	(99,630		)
Net deferred tax asset	$	83,904		$	43,823