Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

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)	2016			2015			2014
Current expense	$	103,335		$	67,025		$	69,612
Deferred expense (benefit)	(16,654		)	4,551			(25,027		)
Tax credits	(7,112		)	(11,268		)	(12,012		)
Amortization on qualified affordable housing tax credits	4,185			2,023			1,005
Tax benefits attributable to items charged to equity and goodwill	1,439			1,763			2,105
	$	85,193		$	64,094		$	35,683

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)	2016			2015			2014
Federal tax based on statutory rate	$	95,189		$	72,428		$	49,373
Increase (decrease) resulting from:
Effect of tax-exempt income	(8,203		)	(6,919		)	(7,064		)
Interest and other nondeductible expenses	3,250			5,899			2,642
State taxes, net of federal benefit	4,770			3,955			2,531
Tax credits	(7,112		)	(11,268		)	(12,012		)
Amortization on qualified affordable housing tax credits	4,185			2,023			1,005
Other	(6,886		)	(2,024		)	(792		)
	$	85,193		$	64,094		$	35,683
Effective tax rate	31.3		%	31.0		%	25.3		%

Deferred Tax Assets and Liabilities

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

(Dollars in thousands)	2016			2015
Deferred tax asset:
NOL carryforward	$	19,584		$	17,258
Allowance for credit losses	58,036			56,446
Deferred compensation	10,852			7,528
Basis difference in acquired assets	32,923			48,256
Unrealized loss on securities available for sale	14,019			854
OREO	4,498			6,210
Other	14,754			10,438
	154,666			146,990
Deferred tax liability:
Basis difference in acquired assets	(13,150		)	(31,975		)
Gain on acquisition	—			(212		)
FHLB stock	(270		)	(122		)
Premises and equipment	(6,132		)	(1,658		)
Acquisition intangibles	(8,134		)	(7,648		)
Deferred loan costs	(4,702		)	(4,610		)
Investments acquired	—			(167		)
Other	(9,196		)	(16,694		)
	(41,584		)	(63,086		)
Net deferred tax asset	$	113,082		$	83,904