Income Taxes (Tables)

3 Months Ended

Mar. 31, 2017

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
	March 31,
(dollars in thousands)	2017			2016
Provision at statutory rate of 35%	$	16,269		$	12,827
Tax-exempt income		(4,397	)		(4,168	)
State income taxes		851			583
Interim period effective rate adjustment		(455	)		(148	)
Tax credit investments		(1,876	)		(80	)
Other, net		99			657
Income tax expense	$	10,491		$	9,671
Effective tax rate		22.6	%		26.4	%

Summary of Reconciliation of Unrecognized Tax Benefits

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

(dollars in thousands)	2017		2016
Balance at January 1,	$	777	$	124
Additions based on tax positions related to the current year		32		14
Balance at March 31,	$	809	$	138

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

Significant components of net deferred tax assets (liabilities) were as follows at March 31, 2017 and December 31, 2016:

	March 31,			December 31,
(dollars in thousands)	2017			2016
Deferred Tax Assets
Allowance for loan losses, net of recapture	$	19,730		$	19,773
Benefit plan accruals		15,603			23,846
Alternative minimum tax credit		19,783			19,523
Unrealized losses on benefit plans		194			205
Net operating loss carryforwards		65,690			66,917
Federal tax credits		3,448			35
Other-than-temporary impairment		3,606			3,606
Acquired loans		37,331			40,522
Lease exit obligation		2,440			2,060
Unrealized losses on available-for-sale investment securities		18,088			23,365
Unrealized losses on held-to-maturity investment securities		6,964			7,118
Unrealized losses on hedges		3,212			4,116
Other real estate owned		2,288			3,310
Other, net		2,405			2,675
Total deferred tax assets		200,782			217,071
Deferred Tax Liabilities
Accretion on investment securities		(657	)		(700	)
Purchase accounting		(16,994	)		(17,552	)
Loan servicing rights		(9,584	)		(9,627	)
Premises and equipment		(4,937	)		(4,800	)
Other, net		(3,234	)		(2,529	)
Total deferred tax liabilities		(35,406	)		(35,208	)
Net deferred tax assets	$	165,376		$	181,863