Federal and State Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

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, 2022		December 31, 2021	December 31, 2020
Current
Federal	$	42,951	51,180	47,775
State	21,950		22,596	20,728
Total current income tax expense	64,901		73,776	68,503
Deferred 1
Federal	1,712		(7,151)	(5,396)
State	465		(1,944)	(1,467)
Total deferred income tax expense (benefit)	2,177		(9,095)	(6,863)
Total income tax expense	$	67,078	64,681	61,640

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1 Includes tax benefit of operating loss carryforwards of $315,000 for the years ended December 31, 2022, 2021, and 2020, 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, 2022		December 31, 2021		December 31, 2020
Federal statutory rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal income tax benefit	4.8	%	4.7	%	4.6	%
Tax-exempt interest income	(4.4	%)	(4.2	%)	(4.0	%)
Tax credits	(2.8	%)	(4.8	%)	(4.2	%)
Other, net	(0.5	%)	1.8	%	1.4	%
Effective income tax rate	18.1	%	18.5	%	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, 2022		December 31, 2021
Deferred tax assets
Available-for-sale debt securities	$	157,381	1,156
Allowance for credit losses	52,445		49,375
Operating lease liabilities	11,871		12,103
Employee benefits	11,024		10,868
Deferred compensation	8,211		8,002
Acquisition fair market value adjustments	4,932		6,891
Transferred debt securities	3,017		—
Net operating loss carryforwards	1,253		1,569
Other	2,376		2,787
Total gross deferred tax assets	252,510		92,751
Deferred tax liabilities
Depreciation of premises and equipment	(17,091)		(15,749)
Operating lease ROU assets	(11,004)		(11,293)
Deferred loan costs	(10,083)		(9,264)
Intangibles	(8,212)		(9,760)
Mortgage servicing rights	(3,408)		(3,244)
Transferred debt securities	—		(10,299)
Other	(9,525)		(5,449)
Total gross deferred tax liabilities	(59,323)		(65,058)
Net deferred tax asset	$	193,187	27,693

Income tax return jurisdictions and years subject to examination

The following schedule summarizes the years that remain subject to examination as of December 31, 2022:

	Years ended December 31,
Federal	2010, 2011, 2012, 2013, 2016, 2019, 2020 and 2021
Colorado	2009, 2010, 2011, 2012, 2018, 2019, 2020 and 2021
Arizona & California	2018, 2019, 2020, and 2021
Alabama, Alaska, Arkansas, Connecticut, Florida, Georgia, Idaho, Indiana, Kentucky, Louisiana, Massachusetts, Michigan, Minnesota, Missouri, Montana, New Jersey, New York, North Dakota, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, & Wisconsin	2019, 2020 and 2021
Iowa, Illinois, Kansas, Maryland, Mississippi, North Carolina, Oregon	2020 and 2021
Hawaii, New Hampshire, New Mexico, Oklahoma	2021