Federal and State Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Summary of consolidated income tax expense

The following table is a summary of consolidated income tax expense:

	Years ended
(Dollars in thousands)	December 31, 2021		December 31, 2020	December 31, 2019
Current
Federal	$	51,180	47,775	34,461
State	22,596		20,728	14,545
Total current income tax expense	73,776		68,503	49,006
Deferred 1
Federal	(7,151)		(5,396)	(279)
State	(1,944)		(1,467)	(77)
Total deferred income tax benefit expense	(9,095)		(6,863)	(356)
Total income tax expense	$	64,681	61,640	48,650

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1 Includes tax benefit of operating loss carryforwards of $315,000, $315,000 and $317,000 for the years ended December 31, 2021, 2020, and 2019, respectively.

Summary of effective tax rate

Combined federal and state income tax expense differs from that computed at the federal statutory corporate income tax rate as follows:

	Years ended
	December 31, 2021		December 31, 2020		December 31, 2019
Federal statutory rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal income tax benefit	4.7	%	4.6	%	4.4	%
Tax-exempt interest income	(4.2	%)	(4.0	%)	(3.7	%)
Tax credits	(4.8	%)	(4.2	%)	(4.5	%)
Other, net	1.8	%	1.4	%	1.6	%
Effective income tax rate	18.5	%	18.8	%	18.8	%

Summary of net deferred tax asset

The tax effect of temporary differences which give rise to a significant portion of deferred tax assets and deferred tax liabilities are as follows:

(Dollars in thousands)	December 31, 2021		December 31, 2020
Deferred tax assets
Allowance for credit losses	$	49,375	44,040
Operating lease liabilities	12,103		12,551
Employee benefits	10,868		9,309
Deferred compensation	8,002		7,638
Acquisition fair market value adjustments	6,891		4,398
Net operating loss carryforwards	1,569		1,884
Available-for-sale debt securities	1,156		—
Other	2,787		2,262
Total gross deferred tax assets	92,751		82,082
Deferred tax liabilities
Depreciation of premises and equipment	(15,749)		(14,654)
Operating lease ROU assets	(11,293)		(11,830)
Transferred debt securities	(10,299)		—
Intangibles	(9,760)		(14,671)
Deferred loan costs	(9,264)		(8,940)
Mortgage servicing rights	(3,244)		(2,268)
Available-for-sale debt securities	—		(48,505)
Other	(5,449)		(5,074)
Total gross deferred tax liabilities	(65,058)		(105,942)
Net deferred tax asset (liability)	$	27,693	(23,860)

Income tax return jurisdictions and years subject to examination

The following schedule summarizes the years that remain subject to examination as of December 31, 2021:

	Years ended December 31,
Federal	2010, 2011, 2012, 2013, 2016, 2017, 2018, 2019, and 2020
Colorado	2010, 2011, 2012, 2016, 2017, 2018, 2019, and 2020
Arizona & California	2016, 2017, 2018, 2019, and 2020
Montana, Idaho, Utah, & North Dakota	2017, 2018, 2019, and 2020
Alabama, Alaska, Arkansas, Connecticut, Florida, Georgia, Indiana, Kentucky, Louisiana, Massachusetts, Michigan, Minnesota, Missouri, New Jersey, New York, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, & Wisconsin	2019 and 2020
Iowa, Illinois, Kansas, Maryland, Mississippi, North Carolina, Ohio, Oregon	2020