Income Taxes (Tables)

6 Months Ended

Jun. 30, 2018

Income Tax Disclosure [Abstract]

Summary of Differences in Taxes from Continuing Operations Computed at Statutory Rate

Following is a summary of the major items comprising the differences in taxes from continuing operations computed at the federal statutory rate and as recorded in the consolidated statements of income:

	Three Months Ended June 30,						Six Months Ended June 30,
(dollars in thousands)	2018			2017			2018			2017
Provision at statutory rate (1)	$	10,153		$	17,303		$	21,270		$	33,572
Tax-exempt income:
Tax-exempt interest		(2,237	)		(3,672	)		(4,428	)		(7,374	)
Section 291/265 interest disallowance		73			64			135			121
Company-owned life insurance income		(510	)		(741	)		(1,057	)		(1,493	)
Tax-exempt income		(2,674	)		(4,349	)		(5,350	)		(8,746	)
State income taxes		1,028			195			2,216			1,046
Interim period effective rate adjustment		933			(286	)		1,025			(741	)
Tax credit investments - federal		(4,973	)		(1,877	)		(10,741	)		(3,753	)
Other, net		(122	)		(402	)		882			(303	)
Income tax expense	$	4,345		$	10,584		$	9,302		$	21,075
Effective tax rate		9.0	%		21.4	%		9.2	%		22.0	%

(1) The statutory rate was 21% for the three and six months ended June 30, 2018, compared to 35% for the three and six months ended June 30, 2017.

Summary of Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amounts of unrecognized tax benefits was as follows:

	Six Months Ended June 30,
(dollars in thousands)	2018		2017
Balance at beginning of period	$	874	$	777
Additions based on tax positions related to the current year		—		70
Balance at end of period	$	874	$	847

Schedule of Significant Components of Net Deferred Tax Assets (Liabilities)

Significant components of net deferred tax assets (liabilities) were as follows at June 30, 2018 and December 31, 2017:

(dollars in thousands)	June 30, 2018			December 31, 2017
Deferred Tax Assets
Allowance for loan losses, net of recapture	$	13,842		$	12,958
Benefit plan accruals		12,146			11,080
Alternative minimum tax credit		2,545			25,084
Unrealized losses on benefit plans		94			108
Net operating loss carryforwards		32,915			39,631
Federal tax credits		12,050			5,516
Other-than-temporary impairment		36			1,424
Deferred gain on securities		2,052			—
Acquired loans		23,976			29,669
Lease exit obligation		1,290			1,337
Unrealized losses on available-for-sale investment securities		18,733			14,011
Unrealized losses on held-to-maturity investment securities		2,746			3,630
Unrealized losses on hedges		—			923
Tax credit investments		862			—
Other real estate owned		181			369
Other, net		2,405			829
Total deferred tax assets		125,873			146,569
Deferred Tax Liabilities
Accretion on investment securities		(451	)		(493	)
Purchase accounting		(15,972	)		(16,718	)
Loan servicing rights		(5,970	)		(6,058	)
Premises and equipment		(9,512	)		(10,052	)
Prepaid expenses		(1,277	)		(1,277	)
Tax credit investments		—			(168	)
Unrealized gains on hedges		(742	)		—
Other, net		(1,762	)		(946	)
Total deferred tax liabilities		(35,686	)		(35,712	)
Net deferred tax assets	$	90,187		$	110,857