Federal and State Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Summary of consolidated income tax expense (benefit)

	Years ended
(Dollars in thousands)	December 31, 2013		December 31, 2012	December 31, 2011
Current
Federal	$	18,377	12,718	8,836
State	7,007		5,522	4,191
Total current income tax expense	25,384		18,240	13,027
Deferred
Federal	3,918		708	(11,256	)
State	715		129	(2,052	)
Total deferred income tax expense (benefit)	4,633		837	(13,308	)
Total income tax expense (benefit)	$	30,017	19,077	(281	)

Summary of effective tax rate

	Years ended
	December 31, 2013		December 31, 2012		December 31, 2011
Federal statutory rate	35.0	%	35.0	%	35.0	%
State taxes, net of federal income tax benefit	4.0	%	3.9	%	8.1	%
Tax-exempt interest income	(12.2	)%	(14.0	)%	(65.5	)%
Tax credits	(3.2	)%	(4.2	)%	(22.1	)%
Goodwill impairment charge	—	%	—	%	42.3	%
Other, net	0.3	%	(0.5	)%	0.6	%
Effective tax rate	23.9	%	20.2	%	(1.6	)%

Summary of net deferred tax asset

(Dollars in thousands)	December 31, 2013			December 31, 2012
Deferred tax assets
Allowance for loan and lease losses	$	50,652		50,963
Other real estate owned	8,041			7,685
Deferred compensation	4,837			3,129
Employee benefits	3,132			2,715
Federal income tax credits	2,778			3,543
Interest rate swap agreements	—			6,549
Other	7,813			7,835
Total gross deferred tax assets	77,253			82,419
Deferred tax liabilities
FHLB stock dividends	(10,359		)	(10,143	)
Deferred loan costs	(6,058		)	(5,316	)
Available-for-sale securities	(5,402		)	(37,083	)
Depreciation of premises and equipment	(3,939		)	(5,437	)
Intangibles	(3,099		)	(1,117	)
Interest rate swap agreements	(736		)	—
Other	(4,111		)	(2,929	)
Total gross deferred tax liabilities	(33,704		)	(62,025	)
Net deferred tax asset	$	43,549		20,394

Income tax returns jurisdictions and years subject to examination

	Years ended December 31,
Federal	2009, 2010, 2011 and 2012
Montana	2010, 2011 and 2012
Idaho	2009, 2010, 2011 and 2012
Colorado	2009, 2010, 2011 and 2012
Utah	2010, 2011 and 2012