Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income tax expense consists of the following:



Year ended December 31,	2017		2016		2015
Current:
Federal	$	24.3	$	40.3	$	26.7
State	5.0		5.9		4.5
Total current	29.3		46.2		31.2
Deferred:
Federal	18.4		2.9		11.1
State	2.5		0.5		1.4
Total deferred	20.9		3.4		12.5
Total income tax expense	$	50.2	$	49.6	$	43.7

Schedule of Effective Income Tax Rate Reconciliation

Total income tax expense differs from the amount computed by applying the statutory federal income tax rate of 35% in 2017, 2016 and 2015, respectively, to income before income taxes as a result of the following:



Year ended December 31,	2017			2016			2015
Tax expense at the statutory tax rate	$	54.9		$	50.8		$	45.7
Increase (decrease) in tax resulting from:
Tax-exempt income	(4.5		)	(4.4		)	(4.1		)
State income tax, net of federal income tax benefit	4.9			4.3			3.8
Benefit of stock-based compensation plans	(2.6		)	—			—
Federal tax credits	(2.4		)	(2.1		)	(2.3		)
Benefit due to enactment of federal tax reform	(2.2		)	—			—
Other, net	2.2			1.0			0.6
Tax expense at effective tax rate	$	50.2		$	49.6		$	43.7

Schedule of Deferred Tax Assets and Liabilities

The tax effects of temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax asset (liability) with a tax rate of 21.0% and 35.0% as of December 31, 2017 and December 31, 2016, respectively, relate to the following:



December 31,	2017			2016
Deferred tax assets:
Loans, principally due to allowance for loan losses	$	18.0		$	30.1
Loan discount	6.7			3.1
Investment securities, unrealized losses	5.6			6.6
Employee benefits	11.5			9.3
Non-performing loan interest	1.1			1.2
Other real estate owned write-downs and carrying costs	0.6			1.3
Tax credit carryforwards ⁽¹⁾	3.7			—
Net operating loss carryforwards ⁽²⁾	8.7			—
Other	4.7			2.5
Deferred tax assets	60.6			54.1
Deferred tax liabilities:
Fixed assets, principally differences in bases and depreciation	(6.7		)	(4.7		)
Deferred loan costs	(1.7		)	(3.0		)
Investment in joint venture partnership, principally due to differences in depreciation of partnership assets	(0.8		)	(1.2		)
Prepaid amounts	(0.6		)	(1.5		)
Government agency stock dividends	(1.6		)	(2.3		)
Goodwill and core deposit intangibles	(38.1		)	(42.4		)
Mortgage servicing rights	(5.7		)	(5.5		)
Other	(1.4		)	(0.3		)
Deferred tax liabilities	(56.6		)	(60.9		)
Net deferred tax assets (liabilities)	$	4.0		$	(6.8	)

^{(1) Based on filed tax returns and amounts expected to be reported in current year tax returns (December 31, 2017), we had remaining federal tax credit carryforwards of}^{$3.7 million}^{from acquired companies. The federal tax credits were primarily generated from low income housing and AMT tax credit carryforwards. These tax credits expire beginning in 2027 and ending in 2037 and their use is subject to annual limitations.}

^{(2) As of December 31, 2017, we had remaining federal net operating loss carryforwards of}^{$20.1 million}^{from acquired companies, which is available to offset federal taxable income and state net operating loss carryforwards in amounts which vary by state. The federal net operating losses will expire beginning in 2029 and ending in 2037 and the state net operating losses will expire beginning in 2018 and ending in 2031. The use of these carryforwards is subject to annual limitations.}