Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Current and Deferred Income Tax Expense (Benefit)

The current and deferred amounts of income tax expense were as follows:



	Years Ended December 31,
	2018		2017		2016
	($ in Thousands)
Current
Federal	$	20,246	$	76,525	$	73,781
State	12,593		11,576		2,885
Total current	32,839		88,101		76,666
Deferred
Federal	34,941		19,755		3,338
State	12,006		1,647		7,318
Total deferred	46,947		21,402		10,656
Total income tax expense	$	79,786	$	109,503	$	87,322

Schedule of Deferred Tax Assets and Liabilities

Temporary differences between the amounts reported in the financial statements and the tax bases of assets and liabilities resulted in deferred taxes. Deferred tax assets and liabilities at December 31, 2018 and 2017 were as follows:



	2018			2017
	($ in Thousands)
Deferred tax assets
Allowance for loan losses	$	61,143		$	66,377
Allowance for other losses	8,304			7,095
Accrued liabilities	3,736			3,884
Deferred compensation	24,754			20,015
Benefit of tax loss and credit carryforwards	10,126			8,438
Nonaccrual interest	1,666			1,619
Net unrealized losses on available-for-sale securities	25,731			15,968
Net unrealized losses on pension and postretirement benefits	16,640			9,928
Other	1,916			4,435
Total deferred tax assets	154,015			137,759
Valuation allowance for deferred tax assets	(251		)	(269		)
Total deferred tax assets after valuation allowance	$	153,764		$	137,490
Deferred tax liabilities
Prepaid expenses	$	61,250		$	49,695
Goodwill	20,178			19,144
Mortgage banking activities	17,428			10,949
Deferred loan fee income	11,892			11,467
State deferred taxes	518			2,001
Lease financing	410			535
Bank premises and equipment	18,655			5,063
Purchase accounting	12,414			5,015
Other	684			304
Total deferred tax liabilities	$	143,429		$	104,173
Net deferred tax assets	$	10,335		$	33,317

Summary of Valuation Allowance [Table Text Block]

The changes in the valuation allowance related to net operating losses for 2018 and 2017 were as follows:



	2018			2017
	($ in Thousands)
Valuation allowance for deferred tax assets, beginning of year	$	(269	)	$	—
(Increase) decrease in current year	18			(269		)
Valuation allowance for deferred tax assets, end of year	$	(251	)	$	(269	)

Schedule of Effective Income Tax Rate Reconciliation

The effective income tax rate differs from the statutory federal tax rate. The major reasons for this difference were as follows:



	2018		2017		2016
Federal income tax rate at statutory rate	21.0	%	35.0	%	35.0	%
Increases (decreases) resulting from:
Tax-exempt interest and dividends	(2.6	)%	(4.1	)%	(4.8	)%
State income taxes (net of federal benefit)	3.7	%	2.9	%	2.5	%
Bank owned life insurance	(0.7	)%	(1.7	)%	(1.7	)%
Tax effect of tax credits and benefits, net of related expenses	(0.7	)%	(0.7	)%	(1.0	)%
Tax reserve adjustments / settlements	1.5	%	(1.2	)%	0.3	%
Net tax benefit from stock-based compensation	(0.5	)%	(1.3	)%	(0.4	)%
Tax Act impact on deferred remeasurement	—	%	3.5	%	—	%
Tax planning in response to the Tax Act	(3.6	)%	—	%	—	%
FDIC premium	0.9	%	—	%	—	%
Other	0.3	%	(0.1	)%	0.5	%
Effective income tax rate	19.3	%	32.3	%	30.4	%

Summary Unrecognized Tax Benefits

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



	2018			2017
	($ in Millions)
Balance at beginning of year	$	4		$	10
Subtractions for tax positions related to prior years	—			(5		)
Subtractions for settlements with tax authorities	(3		)	(1		)
Additions for tax positions related to current year	1			—
Balance at end of year	$	2		$	4