Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Current and Deferred Income Tax Expense (Benefit)

The current and deferred amounts of income tax expense (benefit) were as follows.



	Years Ended December 31,
	2015			2014			2013
	($ in Thousands)
Current:
Federal	$	82,449		$	74,646		$	50,628
State	2,560			1,000			2,653
Total current	85,009			75,646			53,281
Deferred:
Federal	(10,606		)	(805		)	16,409
State	7,084			10,695			9,511
Total deferred	(3,522		)	9,890			25,920
Total income tax expense	$	81,487		$	85,536		$	79,201

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 were as follows.



	2015		2014
	($ in Thousands)
Deferred tax assets:
Allowance for loan losses	$	106,258	$	99,219
Allowance for other losses	10,906		11,609
Accrued liabilities	6,802		5,773
Deferred compensation	31,677		31,392
State net operating losses	14,154		22,640
Nonaccrual interest	1,901		2,383
Other	5,811		7,929
Total deferred tax assets	177,509		180,945
Deferred tax liabilities:
FHLB stock dividends	2,165		6,367
Prepaid expenses	69,396		68,955
Goodwill	25,770		24,049
Mortgage banking activities	15,704		13,147
Deferred loan fee income	17,770		21,199
State deferred taxes	6,366		9,011
Lease financing	3,042		2,313
Bank premises and equipment	7,491		9,532
Other	9,062		5,501
Total deferred tax liabilities	156,766		160,074
Net deferred tax assets	20,743		20,871
Tax effect of unrealized (gain) loss related to available for sale securities	219		(10,902		)
Tax effect of unrealized loss related to pension and postretirement benefits	20,404		14,468
	20,623		3,566
Net deferred tax assets including items with tax effect recorded directly to OCI	$	41,366	$	24,437

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.



	2015		2014		2013
Federal income tax rate at statutory rate	35.0	%	35.0	%	35.0	%
Increases (decreases) resulting from:
Tax-exempt interest and dividends	(5.0	)%	(4.6	)%	(4.5	)%
State income taxes (net of federal benefit)	2.3	%	2.8	%	2.9	%
Bank owned life insurance	(1.2	)%	(1.7	)%	(1.5	)%
Federal tax credits	(0.5	)%	(1.4	)%	(1.0	)%
Tax reserve adjustments	(0.6	)%	0.7	%	(1.9	)%
Other	0.2	%	0.2	%	0.6	%
Effective income tax rate	30.2	%	31.0	%	29.6	%

Summary Unrecognized Tax Benefits

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



	2015			2014
	($ in Millions)
Balance at beginning of year	$	9		$	6
Additions (subtractions) for tax positions related to prior years	(2		)	1
Additions for tax positions related to current year	2			2
Balance at end of year	$	9		$	9