Great Southern Bancorp (GSBC) 10-K 5 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Mar. 02, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Entity File Number	0-18082
Entity Registrant Name	GREAT SOUTHERN BANCORP, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	43-1524856
Entity Address, Address Line One	1451 E. Battlefield
Entity Address, City or Town	Springfield
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	65804
City Area Code	417
Local Phone Number	887-4400
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	GSBC
Trading Exchange	NASDAQ
Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Catagory	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Number of common stock shares outstanding		13,690,119
Entity Public Float			$ 438,764,780
Entity Central Index Key	0000854560
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash	$ 92,403	$ 99,299
Interest-bearing deposits in other financial institutions	471,326	120,856
Cash and cash equivalents	563,729	220,155
Available-for-sale securities	414,933	374,175
Mortgage loans held for sale	17,780	9,242
Loans receivable, net of allowance for loan losses of $55,743 and $40,294 at December 31, 2020 and 2019, respectively	4,296,804	4,153,982
Interest receivable	12,793	13,530
Prepaid expenses and other assets	58,889	74,984
Other real estate owned and repossessions, net	1,877	5,525
Premises and equipment, net	139,170	141,908
Goodwill and other intangible assets	6,944	8,098
Federal Home Loan Bank stock and other interest earning assets	9,806	13,473
Current and deferred income taxes	3,695	0
Total Assets	5,526,420	5,015,072
Liabilities
Deposits	4,516,903	3,960,106
Securities sold under reverse repurchase agreements with customers	164,174	84,167
Short-term borrowings and other interest-bearing liabilities	1,518	228,157
Subordinated debentures issued to capital trust	25,774	25,774
Subordinated notes	148,397	74,276
Accrued interest payable	2,594	4,250
Advances from borrowers for taxes and insurance	7,536	7,484
Accrued expenses and other liabilities	29,783	24,904
Current and deferred income taxes	0	2,888
Total Liabilities	4,896,679	4,412,006
Commitments and Contingencies
Stockholders' Equity
Serial preferred stock, $.01 par value; authorized 1,000,000 shares; issued and outstanding 2020 and 2019 - -0- shares	0	0
Common stock, $.01 par value; authorized 20,000,000 shares; issued and outstanding 2020 -13,752,605 shares, 2019 -14,261,052 shares	138	143
Additional paid-in capital	35,004	33,510
Retained earnings	541,448	537,167
Accumulated other comprehensive income, net of income taxes of $15,699 and $9,525 at December 31, 2020 and 2019, respectively	53,151	32,246
Total stockholders' equity	629,741	603,066
Total Liabilities and Stockholders' equity	$ 5,526,420	$ 5,015,072

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Consolidated Statements of Financial Condition
Loans and Leases Receivable, Allowance	$ 55,743	$ 40,294
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	1,000,000	1,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Shares, Issued	13,752,605	14,261,052
Common Stock, Shares, Outstanding	13,752,605	14,261,052
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$ 15,699	$ 9,525

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest Income
Loans	$ 204,964	$ 223,047	$ 198,226
Investment securities and other	12,739	11,947	7,723
Interest and Dividend Income, Operating	217,703	234,994	205,949
Interest Expense
Deposits	32,431	45,570	27,957
Federal Home Loan Bank advances	0	0	3,985
Short-term borrowings and repurchase agreements	675	3,635	765
Subordinated debentures issued to capital trust	628	1,019	953
Subordinated notes	6,831	4,378	4,097
Interest Expense	40,565	54,602	37,757
Provision for Loan Losses	15,871	6,150	7,150
Net Interest Income	177,138	180,392	168,192
Net Interest Income After Provision for Loan Losses	161,267	174,242	161,042
Noninterest Income
Commissions	892	889	1,137
Service charges, debit card and ATM fees	18,684	20,898	21,695
Net gains on loan sales	8,089	2,607	1,788
Net realized gains (losses) on sales of available-for-sale securities	78	(62)	2
Late charges and fees on loans	1,419	1,432	1,622
Gain (loss) on derivative interest rate products	(264)	(104)	25
Gain on sale of business units	0	0	7,414
Other income	6,152	5,297	2,535
Noninterest Income	35,050	30,957	36,218
Noninterest Expense
Salaries and employee benefits	70,810	63,224	60,215
Net occupancy and equipment expense	27,582	26,217	25,628
Postage	3,069	3,198	3,348
Insurance	2,405	2,015	2,674
Advertising	2,631	2,808	2,460
Office supplies and printing	1,016	1,077	1,047
Telephone	3,794	3,580	3,272
Legal, audit and other professional fees	2,378	2,624	3,423
Expense on other real estate and repossessions	2,023	2,184	4,919
Partnership tax credit investment amortization	80	365	575
Acquired deposit intangible asset amortization	1,154	1,190	1,562
Other operating expenses	6,283	6,656	6,187
Noninterest Expense	123,225	115,138	115,310
Income Before Income Taxes	73,092	90,061	81,950
Provision for Income Taxes	13,779	16,449	14,841
Net Income and Net Income Available to Common Shareholders	$ 59,313	$ 73,612	$ 67,109
Earnings Per Common Share
Basic	$ 4.22	$ 5.18	$ 4.75
Diluted	$ 4.21	$ 5.14	$ 4.71

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Comprehensive Income
Net Income	$ 59,313	$ 73,612	$ 67,109
Unrealized appreciation (depreciation) on available-for-sale securities, net of taxes (credit) of $4,215, $2,574 and $(353) for 2020, 2019 and 2018, respectively	14,274	8,714	(1,229)
Less: reclassification adjustment for losses (gains) included in net income, net of taxes (credit) of $18, $(14) and $0 for 2020, 2019 and 2018, respectively	(60)	48	(2)
Amortization of realized gain on termination of cash flow hedge, net of taxes (credit) of $(1,541), $0 and $0, for 2020, 2019, and 2018, respectively	(5,223)	0	0
Change in fair value of cash flow hedge, net of taxes of $3,519, $4,093 and $2,761 for 2020, 2019 and 2018, respectively	11,914	13,857	9,345
Other comprehensive income	20,905	22,619	8,114
Comprehensive Income	$ 80,218	$ 96,231	$ 75,223

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Comprehensive Income
Tax Effect of Unrealized Appreciation (Depreciation) on Available for Sale Securities Taxes (Credit)	$ 4,215	$ 2,574	$ (353)
Tax Effect Reclassification Adjustment for Gains Included in Net Income Taxes (Credit) Taxes	18	(14)	0
Tax effect on amortization of realized gain on termination of cash flow hedge taxes (credit)	(1,541)	0	0
Tax effect of change in fair value of cash flow hedge taxes (credit)	$ 3,519	$ 4,093	$ 2,761

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total
Equity Balance at Dec. 31, 2017		$ 141	$ 28,203	$ 442,077	$ 1,241		$ 471,662
Net Income				67,109			67,109
Stock issued under Stock Option Plan			1,918			$ 1,043	2,961
Common dividends declared	[1]			(16,966)			(16,966)
Purchase of the Company's common stock						(903)	(903)
Reclassification of stranded tax effects resulting from change in Federal income tax rate				(272)	272
Other comprehensive gain					8,114		8,114
Reclassification of treasury stock per Maryland law		1		139		(140)
Equity Balance at Dec. 31, 2018		142	30,121	492,087	9,627		531,977
Net Income				73,612			73,612
Stock issued under Stock Option Plan			3,389			1,691	5,080
Common dividends declared	[2]			(29,373)			(29,373)
Purchase of the Company's common stock						(849)	(849)
Other comprehensive gain					22,619		22,619
Reclassification of treasury stock per Maryland law		1		841		(842)
Equity Balance at Dec. 31, 2019		143	33,510	537,167	32,246		603,066
Net Income				59,313			59,313
Stock issued under Stock Option Plan			1,494			320	1,814
Common dividends declared	[3]			(33,253)			(33,253)
Purchase of the Company's common stock						(22,104)	(22,104)
Other comprehensive gain					20,905		20,905
Reclassification of treasury stock per Maryland law		(5)		(21,779)		$ 21,784
Equity Balance at Dec. 31, 2020		$ 138	$ 35,004	$ 541,448	$ 53,151		$ 629,741
[1]	$1.20 per share dividend.
[2]	$2.07 per share dividend.
[3]	$2.36 per share dividend.

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Stockholders' Equity
Dividend declared per share	$ 2.36	$ 2.07	$ 1.20

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net income	$ 59,313,000	$ 73,612,000	$ 67,109,000
Proceeds from sales of loans held for sale	317,173,000	131,014,000	92,422,000
Originations of loans held for sale	(316,125,000)	(135,937,000)	(83,806,000)
Items not requiring (providing) cash
Depreciation	10,007,000	9,557,000	9,118,000
Amortization	2,075,000	2,068,000	2,291,000
Compensation expense for stock option grants	1,153,000	922,000	737,000
Provision for loan losses	15,871,000	6,150,000	7,150,000
Net gains on loan sales	(8,089,000)	(2,607,000)	(1,788,000)
Net realized (gains) losses on available-for-sale securities	(78,000)	62,000	(2,000)
Loss (gain) on sale of premises and equipment	(37,000)	77,000	193,000
Loss on sale/write-down of other real estate and repossessions	840,000	316,000	1,886,000
Gain on sale of business units	0	0	(7,414,000)
Accretion of deferred income, premiums, discounts and other	(6,147,000)	(3,899,000)	(2,918,000)
Loss (gain) on derivative interest rate products	264,000	104,000	(25,000)
Deferred income taxes	(11,480,000)	1,074,000	(4,450,000)
Changes in
Interest receivable	362,000	(82,000)	(1,110,000)
Prepaid expenses and other assets	(17,163,000)	(1,336,000)	3,002,000
Accrued expenses and other liabilities	(612,000)	2,725,000	280,000
Income taxes refundable/payable	(1,279,000)	2,599,000	11,520,000
Net cash provided by operating activities	46,048,000	86,419,000	94,195,000
Investing Activities
Net change in loans	(62,493,000)	(81,320,000)	(147,945,000)
Purchase of loans	(92,099,000)	(97,162,000)	(128,038,000)
Cash paid for sale of business units	0	0	(50,356,000)
Cash received for termination of interest rate derivative	45,864,000	0	0
Purchase of premises and equipment	(8,224,000)	(11,789,000)	(9,317,000)
Proceeds from sale of premises and equipment	781,000	204,000	2,328,000
Proceeds from sale of other real estate and repossessions	4,096,000	15,244,000	20,426,000
Capitalized costs on other real estate owned	(126,000)	(121,000)	(153,000)
Proceeds from maturities, calls and repayments of held-to-maturity securities	0	0	130,000
Proceeds from sale of available-for-sale securities	19,236,000	53,695,000	502,000
Proceeds from maturities, calls and repayments of available-for-sale securities	76,248,000	34,769,000	25,734,000
Purchase of available-for-sale securities	(118,296,000)	(207,634,000)	(93,378,000)
Redemption (purchase) of Federal Home Loan Bank stock and other interest-earning assets	3,667,000	(1,035,000)	(1,256,000)
Net cash used in investing activities	(131,346,000)	(295,149,000)	(381,323,000)
Financing Activities
Net increase (decrease) in certificates of deposit	(330,306,000)	129,748,000	242,955,000
Net increase (decrease) in checking and savings accounts	887,114,000	105,400,000	(53,956,000)
Proceeds from Federal Home Loan Bank advances	0	0	2,621,500,000
Repayments of Federal Home Loan Bank advances	0	0	(2,749,000,000)
Net increase (decrease) in shortterm borrowings and other interest-bearing liabilities	(146,632,000)	14,346,000	200,843,000
Advances from (to) borrowers for taxes and insurance	52,000	2,392,000	(227,000)
Proceeds from issuance of subordinated notes	73,513,000	0	0
Purchase of the company's common stock	(22,104,000)	(849,000)	(903,000)
Dividends paid	(33,426,000)	(29,052,000)	(15,819,000)
Stock options exercised	661,000	4,158,000	2,224,000
Net cash provided by financing activities	428,872,000	226,143,000	247,617,000
Increase (Decrease) in Cash and Cash Equivalents	343,574,000	17,413,000	(39,511,000)
Cash and Cash Equivalents, Beginning of Year	220,155,000	202,742,000	242,253,000
Cash and Cash Equivalents, End of Year	$ 563,729,000	$ 220,155,000	$ 202,742,000

Nature of Operations and Summar

Nature of Operations and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Summary of Significant Accounting Policies
Nature of Operations and Summary of Significant Accounting Policies	Note 1: Nature of Operations and Summary of Significant Accounting Policies Nature of Operations and Operating Segments Great Southern Bancorp, Inc. (“GSBC” or the “Company”) operates as a one-bank holding company. GSBC’s business primarily consists of the operations of Great Southern Bank (the “Bank”), which provides a full range of financial services to customers primarily located in Missouri, Iowa, Kansas, Minnesota, Nebraska and Arkansas. The Bank also originates commercial loans from lending offices in Atlanta, Ga., Chicago, Ill., Dallas, Texas, Denver, Colo., Omaha, Neb. and Tulsa, Okla. The Company and the Bank are subject to regulation by certain federal and state agencies and undergo periodic examinations by those regulatory agencies. The Company’s banking operation is its only reportable segment. The banking operation is principally engaged in the business of originating residential and commercial real estate loans, construction loans, commercial business loans and consumer loans and funding these loans by attracting deposits from the general public, accepting brokered deposits and borrowing from the Federal Home Loan Bank and others. The operating results of this segment are regularly reviewed by management to make decisions about resource allocations and to assess performance. Selected information is not presented separately for the Company’s reportable segment, as there is no material difference between that information and the corresponding information in the consolidated financial statements. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses and the valuation of real estate acquired in connection with foreclosures or in satisfaction of loans, the valuation of loans acquired with indication of impairment and other-than-temporary impairments (OTTI) and fair values of financial instruments. In connection with the determination of the allowance for loan losses and the valuation of foreclosed assets held for sale, management obtains independent appraisals for significant properties. In addition, the Company considers that the determination of the carrying value of goodwill and intangible assets involves a high degree of judgment and complexity. Principles of Consolidation The consolidated financial statements include the accounts of Great Southern Bancorp, Inc., its wholly owned subsidiary, the Bank, and the Bank’s wholly owned subsidiaries, Great Southern Real Estate Development Corporation, GSB One LLC (including its wholly owned subsidiary, GSB Two LLC), Great Southern Financial Corporation, Great Southern Community Development Company, LLC (including its wholly owned subsidiary, Great Southern CDE, LLC), GS, LLC, GSSC, LLC, GSTC Investments, LLC, GS-RE Holding, LLC (including its wholly owned subsidiary, GS RE Management, LLC), GS-RE Holding II, LLC, GS-RE Holding III, LLC, VFP Conclusion Holding, LLC and VFP Conclusion Holding II, LLC. All significant intercompany accounts and transactions have been eliminated in consolidation. Federal Home Loan Bank Stock Federal Home Loan Bank common stock is a required investment for institutions that are members of the Federal Home Loan Bank system. The required investment in common stock is based on a predetermined formula, carried at cost and evaluated for impairment. Securities Available-for-sale securities, which include any security for which the Company has no immediate plan to sell but which may be sold in the future, are carried at fair value. Unrealized gains and losses are recorded, net of related income tax effects, in other comprehensive income. Held-to-maturity securities, which include any security for which the Company has the positive intent and ability to hold until maturity, are carried at historical cost adjusted for amortization of premiums and accretion of discounts. Amortization of premiums and accretion of discounts are recorded as interest income from securities. Realized gains and losses are recorded as net security gains (losses). Gains and losses on sales of securities are determined on the specific-identification method. For debt securities with fair value below carrying value when the Company does not intend to sell a debt security, and it is more likely than not the Company will not have to sell the security before recovery of its cost basis, it recognizes the credit component of an other-than-temporary impairment (“OTTI”) of a debt security in earnings and the remaining portion in other comprehensive income. For held-to-maturity debt securities, the amount of an OTTI recorded in other comprehensive income for the noncredit portion of a previous OTTI is amortized prospectively over the remaining life of the security on the basis of the timing of future estimated cash flows of the security. The Company’s consolidated statements of income reflect the full impairment (that is, the difference between the security’s amortized cost basis and fair value) on debt securities that the Company intends to sell or would more likely than not be required to sell before the expected recovery of the amortized cost basis. For available-for-sale and held-to-maturity debt securities that management has no intent to sell and believes that it more likely than not will not be required to sell prior to recovery, only the credit loss component of the impairment is recognized in earnings, while the noncredit loss is recognized in accumulated other comprehensive income. The credit loss component recognized in earnings is identified as the amount of principal cash flows not expected to be received over the remaining term of the security based on cash flow projections. For equity securities, if any, when the Company has decided to sell an impaired available-for-sale security and the Company does not expect the fair value of the security to fully recover before the expected time of sale, the security is deemed OTTI in the period in which the decision to sell is made. The Company recognizes an impairment loss when the impairment is deemed other-than-temporary even if a decision to sell has not been made. Mortgage Loans Held for Sale Mortgage loans originated and intended for sale in the secondary market are carried at the lower of cost or fair value in the aggregate. Write-downs to fair value are recognized as a charge to earnings at the time the decline in value occurs. Nonbinding forward commitments to sell individual mortgage loans are generally obtained to reduce market risk on mortgage loans in the process of origination and mortgage loans held for sale. Gains and losses resulting from sales of mortgage loans are recognized when the respective loans are sold to investors. Fees received from borrowers to guarantee the funding of mortgage loans held for sale and fees paid to investors to ensure the ultimate sale of such mortgage loans are recognized as income or expense when the loans are sold or when it becomes evident that the commitment will not be used. Loans Originated by the Company Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at their outstanding principal balances adjusted for any charge-offs, the allowance for loan losses, any deferred fees or costs on originated loans and unamortized premiums or discounts on purchased loans. Interest income is reported on the interest method and includes amortization of net deferred loan fees and costs over the loan term. Past due status is based on the contractual terms of a loan. Generally, loans are placed on nonaccrual status at 90 days past due and interest is considered a loss, unless the loan is well secured and in the process of collection. Payments received on nonaccrual loans are applied to principal until the loans are returned to accrual status. Loans are returned to accrual status when all payments contractually due are brought current, payment performance is sustained for a period of time, generally six months, and future payments are reasonably assured. With the exception of consumer loans, charge-offs on loans are recorded when available information indicates a loan is not fully collectible and the loss is reasonably quantifiable. Consumer loans are charged-off at specified delinquency dates consistent with regulatory guidelines. Allowance for Loan Losses The allowance for loan losses is established as losses are estimated to have occurred through a provision for loan losses charged to earnings. Loan losses are charged against the allowance when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance consists of allocated and general components. The allocated component relates to loans that are classified as impaired. For loans classified as impaired, an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The general component covers non-classified loans and is based on historical charge-off experience and expected loss given default derived from the Company’s internal risk rating process. Other adjustments may be made to the allowance for certain loan segments after an assessment of internal or external influences on credit quality that are not fully reflected in the historical loss or risk rating data. A loan is considered impaired when, based on current information and events, it is probable that not all of the principal and interest due under the loan agreement will be collected in accordance with contractual terms. For non-homogeneous loans, such as commercial loans, management determines which loans are reviewed for impairment based on information obtained by account officers, weekly past due meetings, various analyses including annual reviews of large loan relationships, calculations of loan debt coverage ratios as financial information is obtained and periodic reviews of all loans over $1.0 million. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length and reasons for the delay, the borrower’s prior payment record and the amount of any collateral shortfall in relation to the principal and interest owed. Large groups of smaller balance homogenous loans, such as consumer and residential loans, are collectively evaluated for impairment. In accordance with regulatory guidelines, impairment in the consumer and mortgage loan portfolio is primarily identified based on past-due status. Consumer and mortgage loans which are over 90 days past due or specifically identified as troubled debt restructurings will generally be individually evaluated for impairment. Impairment is measured on a loan-by-loan basis for both homogeneous and non-homogeneous loans by either the present value of expected future cash flows or the fair value of the collateral if the loan is collateral dependent. Payments made on impaired loans are treated in accordance with the accrual status of the loan. If loans are performing in accordance with their contractual terms but the ultimate collectability of principal and interest is questionable, payments are applied to principal only. Loans Acquired in Business Combinations Loans acquired in business combinations under ASC Topic 805, Business Combinations Fair Value Measurements and Disclosures For acquired loans not acquired in conjunction with an FDIC-assisted transaction that are not considered to be purchased credit-impaired loans, the Company evaluates those loans acquired in accordance with the provisions of ASC Topic 310-20, Nonrefundable Fees and Other Costs Loans and Debt Securities Acquired with Deteriorated Credit Quality The Company evaluates all of its loans acquired in conjunction with its FDIC-assisted transactions in accordance with the provisions of ASC Topic 310-30. For purposes of applying ASC 310-30, loans acquired in FDIC-assisted business combinations are aggregated into pools of loans with common risk characteristics. All loans acquired in the FDIC transactions, both covered and not covered by loss sharing agreements, were deemed to be purchased credit-impaired loans as there is general evidence of credit deterioration since origination in the pools and there is some probability that not all contractually required payments will be collected. As a result, related discounts are recognized subsequently through accretion based on changes in the expected cash flows of these acquired loans. The expected cash flows of the acquired loan pools in excess of the fair values recorded is referred to as the accretable yield and is recognized in interest income over the remaining estimated lives of the loan pools for impaired loans accounted for under ASC Topic 310-30. Subsequent to acquisition date, the Company has estimated cash flows expected to be collected on pools of loans sharing common risk characteristics, which are treated in the aggregate when applying various valuation techniques. Increases in the Company’s cash flow expectations have been recognized as increases to the accretable yield while decreases have been recognized as impairments through the allowance for loan losses. Other Real Estate Owned and Repossessions Assets acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value less estimated cost to sell at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, valuations are periodically performed by management and the assets are carried at the lower of carrying amount or fair value less estimated cost to sell. Revenue and expenses from operations and changes in the valuation allowance are included in net expense on foreclosed assets. Other real estate owned also includes bank premises formerly, but no longer, used for banking, as well as property originally acquired for future expansion but no longer intended to be used for that purpose. Premises and Equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation is charged to expense using the straight-line and accelerated methods over the estimated useful lives of the assets. Leasehold improvements are capitalized and amortized using the straight-line and accelerated methods over the terms of the respective leases or the estimated useful lives of the improvements, whichever is shorter. Material lease obligations consist of leases for various loan offices and banking centers, all of which are categorized as “operating leases.” Under current accounting guidance, lessees are required to recognize a lease liability and a right-of-use asset for these leases. This right-of-use asset is included in Premises and Equipment. Long-Lived Asset Impairment The Company evaluates the recoverability of the carrying value of long-lived assets whenever events or circumstances indicate the carrying amount may not be recoverable. If a long-lived asset is tested for recoverability and the undiscounted estimated future cash flows expected to result from the use and eventual disposition of the asset is less than the carrying amount of the asset, the asset cost is adjusted to fair value and an impairment loss is recognized as the amount by which the carrying amount of a long-lived asset exceeds its fair value. No asset impairment was recognized during the years ended December 31, 2020, 2019 and 2018. Goodwill and Intangible Assets Goodwill is evaluated annually for impairment or more frequently if impairment indicators are present. The annual, or interim, goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount and an impairment charge is recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. The Company still may perform the qualitative assessment for a reporting unit to determine if the qualitative impairment test is necessary. Intangible assets are being amortized on the straight-line basis generally over a period of seven years . Such assets are periodically evaluated as to the recoverability of their carrying value. A summary of goodwill and intangible assets is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Goodwill – Branch acquisitions ​ $ 5,396 ​ $ 5,396 Deposit intangibles ​ ​ Boulevard Bank ​ 31 ​ 153 Valley Bank ​ 200 ​ 600 Fifth Third Bank ​ 1,317 ​ 1,949 ​ ​ 1,548 ​ 2,702 ​ ​ $ 6,944 ​ $ 8,098 ​ Loan Servicing and Origination Fee Income Loan servicing income represents fees earned for servicing real estate mortgage loans owned by various investors. The fees are generally calculated on the outstanding principal balances of the loans serviced and are recorded as income when earned. Loan origination fees, net of direct loan origination costs, are recognized as income using the level-yield method over the contractual life of the loan. Stockholders’ Equity The Company is incorporated in the State of Maryland. Under Maryland law, there is no concept of “Treasury Shares.” Instead, shares purchased by the Company constitute authorized but unissued shares under Maryland law. Accounting principles generally accepted in the United States of America state that accounting for treasury stock shall conform to state law. The cost of shares purchased by the Company has been allocated to common stock and retained earnings balances. Earnings Per Common Share Basic earnings per common share are computed based on the weighted average number of common shares outstanding during each year. Diluted earnings per common share are computed using the weighted average common shares and all potential dilutive common shares outstanding during the period. Earnings per common share (EPS) were computed as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income and net income available to common shareholders ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common shares outstanding ​ 14,043 ​ 14,201 ​ 14,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common share stock options outstanding ​ 61 ​ 129 ​ 128 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average diluted common shares ​ 14,104 ​ 14,330 ​ 14,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – basic ​ $ 4.22 ​ $ 5.18 ​ $ 4.75 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – diluted ​ $ 4.21 ​ $ 5.14 ​ $ 4.71 ​ Options outstanding at December 31, 2020, 2019 and 2018, to purchase 758,901, 201,400 and 424,833 shares of common stock, respectively, were not included in the computation of diluted earnings per common share for each of the years because the exercise prices of such options were greater than the average market prices of the common stock for the years ended December 31, 2020, 2019 and 2018, respectively. Stock Compensation Plans The Company has stock-based employee compensation plans, which are described more fully in Note 20 . In accordance with FASB ASC 718, Compensation – Stock Compensation , compensation cost related to share-based payment transactions is recognized in the Company’s consolidated financial statements based on the grant-date fair value of the award using the modified prospective transition method. For the years ended December 31, 2020, 2019 and 2018, share-based compensation expense totaling $1.2 million, $922,000 and $737,000, respectively, was included in salaries and employee benefits expense in the consolidated statements of income. Cash Equivalents The Company considers all liquid investments with original maturities of three months or less to be cash equivalents. At December 31, 2020 and 2019, cash equivalents consisted of interest-bearing deposits in other financial institutions. At December 31, 2020, nearly all of the interest-bearing deposits were uninsured with nearly all of these balances held at the Federal Home Loan Bank or the Federal Reserve Bank. Income Taxes The Company accounts for income taxes in accordance with income tax accounting guidance (FASB ASC 740, Income Taxes Deferred income tax expense results from changes in deferred tax assets and liabilities between periods. Deferred tax assets are recognized if it is more likely than not, based on the technical merits, that the tax position will be realized or sustained upon examination. The term “more likely than not” means a likelihood of more than 50 percent; the terms examined and upon examination also include resolution of the related appeals or litigation processes, if any. A tax position that meets the more-likely-than-not recognition threshold is initially and subsequently measured as the largest amount of tax benefit that has a greater than 50 percent likelihood of being realized upon settlement with a taxing authority that has full knowledge of all relevant information. The determination of whether or not a tax position has met the more-likely-than-not recognition threshold considers the facts, circumstances and information available at the reporting date and is subject to management’s judgment. Deferred tax assets are reduced by a valuation allowance if, based on the weight of evidence available, it is more likely than not that some portion or all of a deferred tax asset will not be realized. At December 31, 2020 and 2019, no valuation allowance was established. The Company recognizes interest and penalties on income taxes as a component of income tax expense. The Company files consolidated income tax returns with its subsidiaries. Derivatives and Hedging Activities FASB ASC 815, Derivatives and Hedging Note 16 As required by FASB ASC 815, the Company records all derivatives in the statement of financial condition at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Restriction on Cash and Due From Banks The Bank is required to maintain reserve funds in cash and/or on deposit with the Federal Reserve Bank. During the COVID-19 pandemic, the Federal Reserve Bank has reduced all banks’ reserve requirements to $-0- until further notice. There was no reserve required at December 31, 2020, compared to $69.4 million at December 31, 2019. Recent Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326) . The Update amends guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, Topic 326 eliminates the probable initial recognition threshold in current GAAP and, instead, requires an entity to reflect its current estimate of all expected credit losses. This Update affects entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The amendments affect loans, debt securities, trade receivables, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. The Update was set to be effective for the Company on January 1, 2020. During March 2020, pursuant to the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) and guidance from the Securities and Exchange Commission (the “SEC”) and the Financial Accounting Standards Board (the “FASB”), we elected to delay adoption of the new accounting standard related to accounting for credit losses (“CECL”). In December 2020, additional legislation was enacted that amended certain provisions of the CARES Act. One of the provisions that was affected by this new legislation allowed for the election to further delay the adoption of the CECL accounting standard to January 1, 2022. An adoption date of January 1, 2021, was also an acceptable option and we elected January 1, 2021 as our adoption date for the CECL standard. As a result, our 2020 financial statements are prepared under the existing incurred loss methodology standard for accounting for loan losses. The adoption of the CECL model during the first quarter of 2021 requires us to recognize a one-time cumulative adjustment to our allowance for loan losses and a liability for potential losses related to the unfunded portion of our loans and commitments in order to fully transition from the incurred loss model to the CECL model. Upon initial adoption, we increased the balance of our allowance for credit losses by approximately $12 million and create a liability for potential losses related to the unfunded portion of our loans and commitments by approximately $8 million. The after-tax effect of these adjustments is expected to result in a decrease in our retained earnings of approximately $13 million. These estimates are subject to change as material assumptions are refined and model validations are completed as we finalize our first quarter 2021 financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles: Goodwill and Other: Simplifying the Test for Goodwill Impairment (Topic 350) . To simplify the subsequent measurement of goodwill, the amendments eliminate Step 2 from the goodwill impairment test. The annual, or interim, goodwill impairment test should be performed by comparing the fair value of a reporting unit with its carrying amount and an impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the qualitative impairment test is necessary. The nature of and reason for the change in accounting principle should be disclosed upon transition. The amendments in this update are required for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. The impact of adopting this new guidance during the quarter ended March 31, 2020 did not have a material impact on the Company’s consolidated financial statements. During 2020, the Company performed its annual review of goodwill and intangibles, including consideration of the circumstances brought about by the COVID-19 pandemic and its effect on the valuation of the Company and other bank holding companies. The Company concluded that no impairment of its goodwill and intangible assets had occurred in 2020. In August 2018, the FASB issued ASU 2018-13 , Fair Value Measurement (Topic 820) - Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement . ASU 2018-13 modifies the disclosure requirements on fair value measurements in Topic 820. The amendments in this update remove disclosures that no longer are considered cost beneficial, modify/clarify the specific requirements of certain disclosures, and add disclosure requirements identified as relevant. ASU 2018-13 is effective for periods beginning after December 15, 2019. The impact of adopting this new guidance during the quarter ended March 31, 2020 did not have a material impact on the Company’s consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope.

Investments in Securities

Investments in Securities	12 Months Ended
	Dec. 31, 2020
Investments in Securities
Investments in Securities	Note 2: Investments in Securities The amortized cost and fair values of securities classified as available-for-sale were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ Cost Gains Losses Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 151,106 ​ $ 19,665 ​ $ 831 ​ $ 169,940 Agency collateralized mortgage obligations ​ 168,472 ​ 8,524 ​ 375 ​ 176,621 States and political subdivisions securities ​ 45,196 ​ 2,135 ​ 6 ​ 47,325 Small Business Administration securities ​ 20,033 ​ 1,014 ​ — ​ 21,047 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 384,807 ​ $ 31,338 ​ $ 1,212 ​ $ 414,933 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ Cost Gains Losses Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities $ 156,591 $ 8,716 $ 265 $ 165,042 Agency collateralized mortgage obligations ​ ​ 149,980 ​ ​ 2,891 ​ ​ 921 ​ ​ 151,950 States and political subdivisions securities ​ ​ 33,757 ​ ​ 1,368 ​ ​ — ​ ​ 35,125 Small Business Administration securities ​ ​ 22,132 ​ ​ — ​ ​ 74 ​ ​ 22,058 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 362,460 $ 12,975 $ 1,260 $ 374,175 ​ At December 31, 2020, the Company’s agency mortgage-backed securities portfolio consisted of FNMA securities totaling $156.6 million, FHLMC securities totaling $10.3 million and GNMA securities totaling $3.0 million. At December 31, 2020, agency collateralized mortgage obligations consisted of GNMA securities totaling $105.8 million, FNMA securities totaling $52.9 million, and FHLMC securities totaling $17.9 million. At December 31, 2020, all of the Company’s $169.9 million agency mortgage-backed securities had fixed rates of interest. At December 31, 2020, $156.8 million of the Company’s agency collateralized mortgage obligations had fixed rates of interest and $19.8 million had variable rates of interest. The amortized cost and fair value of available-for-sale securities at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Fair ​ Cost Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ After one through five years ​ $ — ​ $ — After five through ten years ​ 8,672 ​ 9,251 After ten years ​ 36,524 ​ 38,074 Securities not due on a single maturity date ​ 339,611 ​ 367,608 ​ ​ $ 384,807 ​ $ 414,933 ​ There were no securities classified as held to maturity at December 31, 2020 or December 31, 2019. The amortized cost and fair values of securities pledged as collateral was as follows at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ Amortized ​ Fair ​ Amortized ​ Fair ​ Cost Value Cost Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public deposits ​ $ 5,674 ​ $ 5,962 ​ $ 8,578 ​ $ 8,913 Collateralized borrowing accounts ​ 188,309 ​ 201,818 ​ 122,771 ​ 129,643 Other ​ 6,413 ​ 6,819 ​ 7,021 ​ 7,107 ​ ​ $ 200,396 ​ $ 214,599 ​ $ 138,370 ​ $ 145,663 ​ Certain investments in debt securities are reported in the financial statements at an amount less than their historical cost. Total fair value of these investments at December 31, 2020 and 2019, was approximately $24.2 million and $116.2 million, respectively, which is approximately 5.8% and 31.1% of the Company’s available-for-sale and held-to-maturity investment portfolio, respectively. Based on evaluation of available evidence, including recent changes in market interest rates, credit rating information and information obtained from regulatory filings, management believes the declines in fair value for these debt securities are temporary. The following table shows the Company’s gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ ​ Fair ​ Unrealized ​ Fair ​ Unrealized ​ Fair ​ Unrealized Description of Securities Value Losses Value Losses Value Losses ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 10,279 ​ $ (831) ​ $ — ​ $ — ​ $ 10,279 ​ $ (831) Agency collateralized mortgage obligations ​ 12,727 ​ (375) ​ — ​ — ​ 12,727 ​ (375) Small Business Administration securities ​ — ​ — ​ — ​ — ​ — ​ — States and political subdivisions securities ​ 1,164 ​ (6) ​ — ​ — ​ 1,164 ​ (6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 24,170 ​ $ (1,212) ​ $ — ​ $ — ​ $ 24,170 ​ $ (1,212) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ ​ Fair ​ Unrealized ​ Fair ​ Unrealized ​ Fair ​ Unrealized Description of Securities Value Losses Value Losses Value Losses ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ — ​ $ — ​ $ 24,762 ​ $ (265) ​ $ 24,762 ​ $ (265) Agency collateralized mortgage obligations ​ ​ 69,372 ​ ​ (921) ​ ​ — ​ ​ — ​ ​ 69,372 ​ ​ (921) Small Business Administration securities ​ 22,058 ​ (74) ​ — ​ — ​ 22,058 ​ (74) States and political subdivisions securities ​ — ​ — ​ — ​ — ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 91,430 ​ $ (995) ​ $ 24,762 ​ $ (265) ​ $ 116,192 ​ $ (1,260) ​ Other-than-Temporary Impairment Upon acquisition of a security, the Company decides whether it is within the scope of the accounting guidance for beneficial interests in securitized financial assets or will be evaluated for impairment under the accounting guidance for investments in debt and equity securities. The accounting guidance for beneficial interests in securitized financial assets provides incremental impairment guidance for a subset of the debt securities within the scope of the guidance for investments in debt and equity securities. For securities where the security is a beneficial interest in securitized financial assets, the Company uses the beneficial interests in securitized financial asset impairment model. For securities where the security is not a beneficial interest in securitized financial assets, the Company uses the debt and equity securities impairment model. The Company does not currently have securities within the scope of this guidance for beneficial interests in securitized financial assets. The Company routinely conducts periodic reviews to identify and evaluate each investment security to determine whether an other-than-temporary impairment has occurred. The Company considers the length of time a security has been in an unrealized loss position, the relative amount of the unrealized loss compared to the carrying value of the security, the type of security and other factors. If certain criteria are met, the Company performs additional review and evaluation using observable market values or various inputs in economic models to determine if an unrealized loss is other than temporary. The Company uses quoted market prices for marketable equity securities and uses broker pricing quotes based on observable inputs for equity investments that are not traded on a stock exchange. For non-agency collateralized mortgage obligations, to determine if the unrealized loss is other than temporary, the Company projects total estimated defaults of the underlying assets (mortgages) and multiplies that calculated amount by an estimate of realizable value upon sale in the marketplace (severity) in order to determine the projected collateral loss. The Company also evaluates any current credit enhancement underlying these securities to determine the impact on cash flows. If the Company determines that a given security position will be subject to a write-down or loss, the Company records the expected credit loss as a charge to earnings. During 2020, 2019 and 2018, no securities were determined to have impairment that had become other-than-temporary. Credit Losses Recognized on Investments During 2020, 2019 and 2018, there were no debt securities that experienced fair value deterioration due to credit losses, as well as due to other market factors, but are not otherwise other-than-temporarily impaired.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2020
Loans and Allowance for Loan Losses
Loans and Allowance for Loan Losses	Note 3: Loans and Allowance for Loan Losses Classes of loans at December 31, 2020 and 2019, included: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) One- to four-family residential construction $ 42,793 $ 33,963 Subdivision construction ​ 30,894 ​ 16,088 Land development ​ 54,010 ​ 40,431 Commercial construction ​ 1,212,837 ​ 1,322,861 Owner occupied one- to four-family residential ​ 470,436 ​ 387,016 Non-owner occupied one- to four-family residential ​ 114,569 ​ 120,343 Commercial real estate ​ 1,553,677 ​ 1,494,172 Other residential ​ 1,021,145 ​ 866,006 Commercial business ​ 370,898 ​ 313,209 Industrial revenue bonds ​ 14,003 ​ 13,189 Consumer auto ​ 86,173 ​ 151,854 Consumer other ​ 40,762 ​ 46,720 Home equity lines of credit ​ 114,689 ​ 118,988 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 98,643 ​ 127,206 ​ ​ 5,225,529 ​ 5,052,046 Undisbursed portion of loans in process ​ (863,722) ​ (850,666) Allowance for loan losses ​ (55,743) ​ (40,294) Deferred loan fees and gains, net ​ (9,260) ​ (7,104) ​ ​ $ 4,296,804 ​ $ 4,153,982 ​ Classes of loans by aging were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Loans ​ ​ ​ ​ ​ ​ ​ ​ Over 90 ​ ​ ​ ​ ​ ​ ​ Total ​ > 90 Days Past ​ ​ 30-59 Days ​ 60-89 Days ​ Days ​ Total Past ​ ​ ​ ​ Loans ​ Due and ​ Past Due Past Due Past Due Due Current Receivable Still Accruing ​ ​ (In Thousands) One- to four-family residential construction ​ $ 1,365 ​ $ — ​ $ — ​ $ 1,365 ​ $ 41,428 ​ $ 42,793 ​ $ — Subdivision construction ​ — ​ — ​ — ​ — ​ 30,894 ​ 30,894 ​ — Land development ​ 20 ​ — ​ — ​ 20 ​ 53,990 ​ 54,010 ​ — Commercial construction ​ — ​ — ​ — ​ — ​ 1,212,837 ​ 1,212,837 ​ — Owner occupied one- to four- family residential ​ 1,379 ​ 113 ​ 1,502 ​ 2,994 ​ 467,442 ​ 470,436 ​ — Non-owner occupied one- to four-family residential ​ — ​ ​ — ​ ​ 69 ​ ​ 69 ​ ​ 114,500 ​ ​ 114,569 ​ — Commercial real estate ​ — ​ 79 ​ 587 ​ 666 ​ 1,553,011 ​ 1,553,677 ​ — Other residential ​ — ​ — ​ — ​ — ​ 1,021,145 ​ 1,021,145 ​ — Commercial business ​ — ​ — ​ 114 ​ 114 ​ 370,784 ​ 370,898 ​ — Industrial revenue bonds ​ — ​ — ​ — ​ — ​ 14,003 ​ 14,003 ​ — Consumer auto ​ 364 ​ 119 ​ 169 ​ 652 ​ 85,521 ​ 86,173 ​ — Consumer other ​ 443 ​ 7 ​ 94 ​ 544 ​ 40,218 ​ 40,762 ​ — Home equity lines of credit ​ 153 ​ 111 ​ 508 ​ 772 ​ 113,917 ​ 114,689 ​ — Loans acquired and accounted for under ASC 310-30, net of discounts ​ 1,662 ​ 641 ​ 3,843 ​ 6,146 ​ 92,497 ​ 98,643 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 5,386 ​ 1,070 ​ 6,886 ​ 13,342 ​ 5,212,187 ​ 5,225,529 ​ — Less: Loans acquired and accounted for under ASC 310-30, net of discounts ​ 1,662 ​ 641 ​ 3,843 ​ 6,146 ​ 92,497 ​ 98,643 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,724 ​ $ 429 ​ $ 3,043 ​ $ 7,196 ​ $ 5,119,690 ​ $ 5,126,886 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Loans ​ ​ ​ ​ ​ ​ ​ ​ Over 90 ​ ​ ​ ​ ​ ​ ​ Total ​ > 90 Days Past ​ ​ 30-59 Days ​ 60-89 Days ​ Days ​ Total Past ​ ​ ​ ​ Loans ​ Due and ​ Past Due Past Due Past Due Due Current Receivable Still Accruing ​ ​ (In Thousands) One- to four-family residential construction ​ $ — ​ $ — ​ $ — ​ $ — ​ $ 33,963 ​ $ 33,963 ​ $ — Subdivision construction ​ — ​ — ​ — ​ — ​ 16,088 ​ 16,088 ​ — Land development ​ — ​ 27 ​ — ​ 27 ​ 40,404 ​ 40,431 ​ — Commercial construction ​ 15,085 ​ — ​ — ​ 15,085 ​ 1,307,776 ​ 1,322,861 ​ — Owner occupied one- to four- family residential ​ 1,453 ​ 1,631 ​ 1,198 ​ 4,282 ​ 382,734 ​ 387,016 ​ — Non-owner occupied one- to four-family residential ​ 152 ​ — ​ 181 ​ 333 ​ 120,010 ​ 120,343 ​ — Commercial real estate ​ 549 ​ 119 ​ 632 ​ 1,300 ​ 1,492,872 ​ 1,494,172 ​ — Other residential ​ 376 ​ — ​ — ​ 376 ​ 865,630 ​ 866,006 ​ — Commercial business ​ 60 ​ — ​ 1,235 ​ 1,295 ​ 311,914 ​ 313,209 ​ — Industrial revenue bonds ​ — ​ — ​ — ​ — ​ 13,189 ​ 13,189 ​ — Consumer auto ​ 1,101 ​ 259 ​ 558 ​ 1,918 ​ 149,936 ​ 151,854 ​ — Consumer other ​ 278 ​ 233 ​ 198 ​ 709 ​ 46,011 ​ 46,720 ​ — Home equity lines of credit ​ 296 ​ — ​ 517 ​ 813 ​ 118,175 ​ 118,988 ​ — Loans acquired and accounted for under ASC 310-30, net of discounts ​ 2,177 ​ 709 ​ 6,191 ​ 9,077 ​ 118,129 ​ 127,206 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 21,527 ​ 2,978 ​ 10,710 ​ 35,215 ​ 5,016,831 ​ 5,052,046 ​ — Less: Loans acquired and accounted for under ASC 310-30, net of discounts ​ 2,177 ​ 709 ​ 6,191 ​ 9,077 ​ 118,129 ​ 127,206 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 19,350 ​ $ 2,269 ​ $ 4,519 ​ $ 26,138 ​ $ 4,898,702 ​ $ 4,924,840 ​ $ — ​ Non-accruing loans are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — ​ $ — Subdivision construction ​ — ​ — Land development ​ — ​ — Commercial construction ​ — ​ — Owner occupied one- to four-family residential ​ 1,502 ​ 1,198 Non-owner occupied one- to four-family residential ​ 69 ​ 181 Commercial real estate ​ 587 ​ 632 Other residential ​ — ​ — Commercial business ​ 114 ​ 1,235 Industrial revenue bonds ​ — ​ — Consumer auto ​ 169 ​ 558 Consumer other ​ 94 ​ 198 Home equity lines of credit ​ 508 ​ 517 ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,043 ​ $ 4,519 ​ The following tables present the activity in the allowance for loan losses by portfolio segment for the years ended December 31, 2020, 2019 and 2018, respectively. Also presented are the balance in the allowance for loan losses and the recorded investment in loans based on portfolio segment and impairment method as of the years ended December 31, 2020, 2019, and 2018, respectively: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2020 ​ $ 4,339 ​ $ 5,153 ​ $ 24,334 ​ $ 3,076 ​ $ 1,355 ​ $ 2,037 ​ $ 40,294 Provision (benefit) charged to expense ​ 84 ​ 4,042 ​ 9,343 ​ 242 ​ 914 ​ 1,246 ​ 15,871 Losses charged off ​ (70) ​ — ​ (43) ​ (1) ​ (28) ​ (3,152) ​ (3,294) Recoveries ​ 183 ​ 180 ​ 73 ​ 204 ​ 149 ​ 2,083 ​ 2,872 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 ​ $ 4,536 ​ $ 9,375 ​ $ 33,707 ​ $ 3,521 ​ $ 2,390 ​ $ 2,214 ​ $ 55,743 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 90 ​ $ — ​ $ 445 ​ $ — ​ $ 14 ​ $ 164 ​ $ 713 Collectively evaluated for impairment ​ $ 4,382 ​ $ 9,282 ​ $ 32,937 ​ $ 3,378 ​ $ 2,331 ​ $ 2,040 ​ $ 54,350 Loans acquired and accounted for under ASC 310-30 ​ $ 64 ​ $ 93 ​ $ 325 ​ $ 143 ​ $ 45 ​ $ 10 ​ $ 680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 3,546 ​ $ — ​ $ 3,438 ​ $ — ​ $ 167 ​ $ 1,897 ​ $ 9,048 Collectively evaluated for impairment ​ $ 655,146 ​ $ 1,021,145 ​ $ 1,550,239 ​ $ 1,266,847 ​ $ 384,734 ​ $ 239,727 ​ $ 5,117,838 Loans acquired and accounted for under ASC 310-30 ​ $ 57,113 ​ $ 6,150 ​ $ 24,613 ​ $ 2,551 ​ $ 2,549 ​ $ 5,667 ​ $ 98,643 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2019 ​ $ 3,122 ​ $ 4,713 ​ $ 19,803 ​ $ 3,105 ​ $ 1,568 ​ $ 6,098 ​ $ 38,409 Provision (benefit) charged to expense ​ 1,625 ​ 603 ​ 4,651 ​ 22 ​ (309) ​ (442) ​ 6,150 Losses charged off ​ (534) ​ (189) ​ (144) ​ (101) ​ (371) ​ (6,723) ​ (8,062) Recoveries ​ 126 ​ 26 ​ 24 ​ 50 ​ 467 ​ 3,104 ​ 3,797 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 ​ $ 4,339 ​ $ 5,153 ​ $ 24,334 ​ $ 3,076 ​ $ 1,355 ​ $ 2,037 ​ $ 40,294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 198 ​ $ — ​ $ 517 ​ $ — ​ $ 13 ​ $ 201 ​ $ 929 Collectively evaluated for impairment ​ $ 3,973 ​ $ 5,101 ​ $ 23,570 ​ $ 2,940 ​ $ 1,306 ​ $ 1,814 ​ $ 38,704 Loans acquired and accounted for under ASC 310-30 ​ $ 168 ​ $ 52 ​ $ 247 ​ $ 136 ​ $ 36 ​ $ 22 ​ $ 661 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 2,960 ​ $ — ​ $ 4,020 ​ $ — ​ $ 1,286 ​ $ 2,001 ​ $ 10,267 Collectively evaluated for impairment ​ $ 554,450 ​ $ 866,006 ​ $ 1,490,152 ​ $ 1,363,292 ​ $ 325,112 ​ $ 315,561 ​ $ 4,914,573 Loans acquired and accounted for under ASC 310-30 ​ $ 74,562 ​ $ 5,334 ​ $ 29,158 ​ $ 3,606 ​ $ 3,356 ​ $ 11,190 ​ $ 127,206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2018 ​ $ 2,108 $ 2,839 $ 18,639 $ 1,767 $ 3,581 $ 7,558 $ 36,492 Provision (benefit) charged to expense ​ 742 ​ 1,982 ​ 1,094 ​ 1,031 ​ (1,613) ​ 3,914 7,150 Losses charged off ​ (62) ​ (525) ​ (102) ​ (87) ​ (1,155) ​ (9,425) (11,356) Recoveries ​ 334 ​ 417 ​ 172 ​ 394 ​ 755 ​ 4,051 6,123 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ $ 3,122 ​ $ 4,713 ​ $ 19,803 ​ $ 3,105 ​ $ 1,568 ​ $ 6,098 $ 38,409 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 694 ​ $ — ​ $ 613 ​ $ — ​ $ 309 ​ $ 425 $ 2,041 Collectively evaluated for impairment ​ $ 2,392 ​ $ 4,681 ​ $ 18,958 ​ $ 3,029 ​ $ 1,247 ​ $ 5,640 $ 35,947 Loans acquired and accounted for under ASC 310-30 ​ $ 36 ​ $ 32 ​ $ 232 ​ $ 76 ​ $ 12 ​ $ 33 $ 421 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 6,116 ​ $ — ​ $ 3,501 ​ $ 14 ​ $ 1,844 ​ $ 2,464 $ 13,939 Collectively evaluated for impairment ​ $ 433,209 ​ $ 784,894 ​ $ 1,367,934 ​ $ 1,461,644 ​ $ 334,214 ​ $ 429,766 $ 4,811,661 Loans acquired and accounted for under ASC 310-30 ​ $ 93,841 ​ $ 12,790 ​ $ 33,620 ​ $ 4,093 ​ $ 4,347 ​ $ 18,960 $ 167,651 ​ The portfolio segments used in the preceding three tables correspond to the loan classes used in all other tables in Note 3 ● The one- to four-family residential and construction segment includes the one- to four-family residential construction, subdivision construction, owner occupied one- to four-family residential and non-owner occupied one- to four-family residential classes. ● The other residential segment corresponds to the other residential class. ● The commercial real estate segment includes the commercial real estate and industrial revenue bonds classes. ● The commercial construction segment includes the land development and commercial construction classes. ● The commercial business segment corresponds to the commercial business class. ● The consumer segment includes the consumer auto, consumer other and home equity lines of credit classes. The weighted average interest rate on loans receivable at December 31, 2020 and 2019, was 4.29% and 4.97%, respectively. Loans serviced for others are not included in the accompanying consolidated statements of financial condition. The unpaid principal balance of loans serviced for others at December 31, 2020, was $462.7 million, consisting of $308.4 million of commercial loan participations sold to other financial institutions and $154.3 million of residential mortgage loans sold. The unpaid principal balance of loans serviced for others at December 31, 2019, was $349.9 million, consisting of $283.0 million of commercial loan participations sold to other financial institutions and $66.9 million of residential mortgage loans sold. In addition, available lines of credit on these loans were $46.1 million and $102.1 million at December 31, 2020 and 2019, respectively. A loan is considered impaired, in accordance with the impairment accounting guidance (FASB ASC 310-10-35-16) when, based on current information and events, it is probable the Company will be unable to collect all amounts due from the borrower in accordance with the contractual terms of the loan. Impaired loans include not only nonperforming loans but also loans modified in troubled debt restructurings where concessions have been granted to borrowers experiencing financial difficulties. The following summarizes information regarding impaired loans at and during the years ended December 31, 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction $ — $ — $ — $ — $ — Subdivision construction ​ 20 ​ 20 ​ — ​ 115 ​ 3 Land development ​ — ​ — ​ — ​ — ​ — Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 3,457 ​ 3,776 ​ 90 ​ 2,999 ​ 169 Non-owner occupied one- to four-family residential ​ 69 ​ 106 ​ — ​ 309 ​ 18 Commercial real estate ​ 3,438 ​ 3,472 ​ 445 ​ 3,736 ​ 135 Other residential ​ — ​ — ​ — ​ — ​ — Commercial business ​ 166 ​ 551 ​ 14 ​ 800 ​ 34 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 865 ​ 964 ​ 140 ​ 932 ​ 91 Consumer other ​ 403 ​ 552 ​ 19 ​ 298 ​ 47 Home equity lines of credit ​ 630 ​ 668 ​ 5 ​ 550 ​ 36 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 9,048 ​ $ 10,109 ​ $ 713 ​ $ 9,739 $ 533 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — ​ $ — ​ $ — ​ $ — $ — Subdivision construction ​ 251 ​ 251 ​ 96 ​ 277 ​ 9 Land development ​ — ​ — ​ — ​ 328 ​ 101 Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 2,300 ​ 2,423 ​ 82 ​ 2,598 ​ 131 Non-owner occupied one- to four-family residential ​ 409 ​ 574 ​ 20 ​ 954 ​ 43 Commercial real estate ​ 4,020 ​ 4,049 ​ 517 ​ 4,940 ​ 264 Other residential ​ — ​ — ​ — ​ — ​ — Commercial business ​ 1,286 ​ 1,771 ​ 13 ​ 1,517 ​ 81 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 1,117 ​ 1,334 ​ 181 ​ 1,128 ​ 125 Consumer other ​ 356 ​ 485 ​ 16 ​ 383 ​ 48 Home equity lines of credit ​ 528 ​ 548 ​ 4 ​ 362 ​ 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 10,267 ​ $ 11,435 ​ $ 929 ​ $ 12,487 $ 839 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2018 ​ December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — $ — ​ $ — ​ $ — ​ $ — Subdivision construction ​ 318 ​ 318 ​ 105 ​ 321 ​ 17 Land development ​ 14 ​ 18 ​ — ​ 14 ​ 1 Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 3,576 ​ 3,926 ​ 285 ​ 3,406 ​ 197 Non-owner occupied one- to four-family residential ​ 2,222 ​ 2,519 ​ 304 ​ 2,870 ​ 158 Commercial real estate ​ 3,501 ​ 3,665 ​ 613 ​ 6,216 ​ 337 Other residential ​ — ​ — ​ — ​ 1,026 ​ 20 Commercial business ​ 1,844 ​ 2,207 ​ 309 ​ 2,932 ​ 362 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 1,874 ​ 2,114 ​ 336 ​ 2,069 ​ 167 Consumer other ​ 479 ​ 684 ​ 72 ​ 738 ​ 59 Home equity lines of credit ​ 111 ​ 128 ​ 17 ​ 412 ​ 28 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 13,939 ​ $ 15,579 ​ $ 2,041 ​ $ 20,004 $ 1,346 ​ At December 31, 2020, $4.8 million of impaired loans had specific valuation allowances totaling $713,000 . At December 31, 2019, $5.2 million of impaired loans had specific valuation allowances totaling $929,000 . At December 31, 2018, $8.4 million of impaired loans had specific valuation allowances totaling $ 2.0 million. For impaired loans which were non-accruing, interest of approximately $579,000, $761,000 and $ 1.0 million would have been recognized on an accrual basis during the years ended December 31, 2020, 2019 and 2018, respectively. Included in certain loan categories in the impaired loans are troubled debt restructurings that were classified as impaired. Troubled debt restructurings are loans that are modified by granting concessions to borrowers experiencing financial difficulties. These concessions could include a reduction in the interest rate on the loan, payment extensions, forgiveness of principal, forbearance or other actions intended to maximize collection. The types of concessions made are factored into the estimation of the allowance for loan losses for troubled debt restructurings primarily using a discounted cash flows or collateral adequacy approach. The following table presents newly restructured loans during the years ended December 31, 2020, 2019 and 2018 by type of modification: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential one-to-four family ​ $ — ​ $ — ​ $ 1,030 ​ $ 1,030 Commercial real estate ​ — ​ — ​ 559 ​ 559 Commercial business ​ — ​ — ​ 22 ​ 22 Consumer ​ — ​ 16 ​ 1,951 ​ 1,967 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ — ​ $ 16 ​ $ 3,562 ​ $ 3,578 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer ​ $ — ​ $ 136 ​ $ — ​ $ 136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ — ​ $ 136 ​ $ — ​ $ 136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential one-to-four family ​ $ 1,348 ​ $ — ​ $ — ​ $ 1,348 Construction and land development ​ ​ — ​ ​ 31 ​ ​ — ​ ​ 31 Commercial construction ​ — ​ — ​ 106 ​ 106 Consumer ​ — ​ 535 ​ — ​ 535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,348 ​ $ 566 ​ $ 106 ​ $ 2,020 ​ At December 31, 2020, the Company had $3.3 million of loans that were modified in troubled debt restructurings and impaired, as follows: $20,000 of construction and land development loans, $1.9 million of single family residential mortgage loans, $646,000 of commercial real estate loans, $127,000 of commercial business loans and $629,000 of consumer loans. Of the total troubled debt restructurings at December 31, 2020, $2.4 million were accruing interest and $1.6 million were classified as substandard using the Company's internal grading system which is described below. The Company had no troubled debt restructurings which were modified in the previous 12 months and subsequently defaulted during the year ended December 31, 2020. When loans modified as troubled debt restructuring have subsequent payment defaults, the defaults are factored into the determination of the allowance for loan losses to ensure specific valuation allowances reflect amounts considered uncollectible. At December 31, 2019, the Company had $1.9 million of loans that were modified in troubled debt restructurings and impaired, as follows: $251,000 of construction and land development loans, $768,000 of single family residential mortgage loans, $412,000 of commercial real estate loans, $156,000 of commercial business loans and $343,000 of consumer loans. Of the total troubled debt restructurings at December 31, 2019, $1.4 million were accruing interest and $562,000 were classified as substandard using the Company’s internal grading system. During the year ended December 31, 2020, borrowers with loans designated as troubled debt restructurings totaling $372,000, all of which consisted of residential one-to-four family loans, met the criteria for placement back on accrual status. This criteria generally includes a minimum of six months of consistent and timely payment performance under original or modified terms. At December 31, 2020, the Company had remaining 65 modified commercial loans with an aggregate principal balance outstanding of $233 million and 581 modified consumer and mortgage loans with an aggregate principal balance outstanding of $18 million. The loan modifications are within the guidance provided by the CARES Act (and its amending legislation), the federal banking regulatory agencies, the Securities and Exchange Commission and the Financial Accounting Standards Board; therefore, they are not considered troubled debt restructurings. The Company reviews the credit quality of its loan portfolio using an internal grading system that classifies loans as “Satisfactory,” “Watch,” “Special Mention,” “Substandard” and “Doubtful.” Loans classified as watch are being monitored because of indications of potential weaknesses or deficiencies that may require future classification as special mention or substandard. Special mention loans possess potential weaknesses that deserve management’s close attention but do not expose the Bank to a degree of risk that warrants substandard classification. Substandard loans are characterized by the distinct possibility that the Bank will sustain some loss if certain deficiencies are not corrected. Doubtful loans are those having all the weaknesses inherent to those classified Substandard with the added characteristics that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions and values, highly questionable and improbable. Loans not meeting any of the criteria previously described are considered satisfactory. The FDIC-assisted acquired loans are evaluated using this internal grading system. These loans are accounted for in pools. Minimal adverse classification in these acquired loan pools was identified as of December 31, 2020 and 2019 respectively. See Note 4 The Company evaluates the loan risk internal grading system definitions and allowance for loan loss methodology on an ongoing basis. The general component of the allowance for loan losses is affected by several factors, including, but not limited to, average historical losses, average life of the loans, current composition of the loan portfolio, current and expected economic conditions, collateral values and internal risk ratings. Management considers all these factors in determining the adequacy of the Company’s allowance for loan losses. No significant changes were made to the loan risk grading system definitions and allowance for loan loss methodology during the past year. The loan grading system is presented by loan class below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Special ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Satisfactory Watch Mention Substandard Doubtful Total ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ 41,428 ​ $ 1,365 ​ $ — ​ $ — ​ $ — ​ $ 42,793 Subdivision construction ​ 30,874 ​ — ​ — ​ 20 ​ — ​ 30,894 Land development ​ 54,010 ​ — ​ — ​ — ​ — ​ 54,010 Commercial construction ​ 1,212,837 ​ — ​ — ​ — ​ — ​ 1,212,837 Owner occupied one- to-four-family residential ​ 467,855 ​ 216 ​ — ​ 2,365 ​ — ​ 470,436 Non-owner occupied one-to-four-family residential ​ 114,176 ​ 324 ​ — ​ 69 ​ — ​ 114,569 Commercial real estate ​ 1,498,031 ​ 52,208 ​ — ​ 3,438 ​ — ​ 1,553,677 Other residential ​ 1,017,648 ​ 3,497 ​ — ​ — ​ — ​ 1,021,145 Commercial business ​ 363,681 ​ 7,102 ​ — ​ 115 ​ — ​ 370,898 Industrial revenue bonds ​ 14,003 ​ — ​ — ​ — ​ — ​ 14,003 Consumer auto ​ 85,657 ​ 5 ​ — ​ 511 ​ — ​ 86,173 Consumer other ​ 40,514 ​ 2 ​ — ​ 246 ​ — ​ 40,762 Home equity lines of credit ​ 114,049 ​ 39 ​ — ​ 601 ​ — ​ 114,689 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 98,633 ​ — ​ — ​ 10 ​ — ​ 98,643 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 5,153,396 ​ $ 64,758 ​ $ — ​ $ 7,375 ​ $ — ​ $ 5,225,529 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Special ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Satisfactory Watch Mention Substandard Doubtful Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ 33,963 ​ $ — ​ $ — ​ $ — ​ $ — ​ $ 33,963 Subdivision construction ​ 16,061 ​ 27 ​ — ​ — ​ — ​ 16,088 Land development ​ 40,431 ​ — ​ — ​ — ​ — ​ 40,431 Commercial construction ​ 1,322,861 ​ — ​ — ​ — ​ — ​ 1,322,861 Owner occupied one- to-four-family residential ​ 385,001 ​ 26 ​ — ​ 1,989 ​ — ​ 387,016 Non-owner occupied one-to-four-family residential ​ 119,743 ​ 419 ​ — ​ 181 ​ — ​ 120,343 Commercial real estate ​ 1,458,400 ​ 32,063 ​ — ​ 3,709 ​ — ​ 1,494,172 Other residential ​ 866,006 ​ — ​ — ​ — ​ — ​ 866,006 Commercial business ​ 307,322 ​ 4,651 ​ — ​ 1,236 ​ — ​ 313,209 Industrial revenue bonds ​ 13,189 ​ — ​ — ​ — ​ — ​ 13,189 Consumer auto ​ 150,874 ​ 47 ​ — ​ 933 ​ — ​ 151,854 Consumer other ​ 46,294 ​ 92 ​ — ​ 334 ​ — ​ 46,720 Home equity lines of credit ​ 118,428 ​ 43 ​ — ​ 517 ​ — ​ 118,988 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 127,192 ​ — ​ — ​ 14 ​ — ​ 127,206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 5,005,765 ​ $ 37,368 ​ $ — ​ $ 8,913 ​ $ — ​ $ 5,052,046 ​ Certain of the Bank’s real estate loans are pledged as collateral for borrowings as set forth in Notes 9 11 Certain directors and executive officers of the Company and the Bank, and their related interests, are customers of and had transactions with the Bank in the ordinary course of business. Except for the interest rates on loans secured by personal residences, in the opinion of management, all loans included in such transactions were made on substantially the same terms as those prevailing at the time for comparable transactions with unrelated parties. Generally, residential first mortgage loans and home equity lines of credit to all employees and directors have been granted at interest rates equal to the Bank’s cost of funds, subject to annual adjustments in the case of residential first mortgage loans and monthly adjustments in the case of home equity lines of credit. At December 31, 2020 and 2019, loans outstanding to these directors and executive officers, and their related interests, are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Balance, beginning of year ​ $ 15,240 ​ $ 29,017 New loans ​ 901 ​ 15,062 Payments ​ (2,673) ​ (28,839) ​ ​ ​ ​ ​ ​ ​ Balance, end of year ​ $ 13,468 ​ $ 15,240 ​

FDIC-Acquired Loans and Loss Sh

FDIC-Acquired Loans and Loss Sharing Agreements	12 Months Ended
	Dec. 31, 2020
FDIC-Acquired Loans and Loss Sharing Agreements
FDIC-Acquired Loans and Loss Sharing Agreements	Note 4: FDIC-Acquired Loans and Loss Sharing Agreements On March 20, 2009, Great Southern Bank entered into a purchase and assumption agreement with loss share with the Federal Deposit Insurance Corporation (FDIC) to assume all of the deposits (excluding brokered deposits) and acquire certain assets of TeamBank, N.A., a full service commercial bank headquartered in Paola, Kansas. The related loss sharing agreement was terminated early, effective April 26, 2016, by mutual agreement of Great Southern Bank and the FDIC. Based upon the acquisition date fair values of the net assets acquired, no goodwill was recorded. On September 4, 2009, Great Southern Bank entered into a purchase and assumption agreement with loss share with the FDIC to assume all of the deposits and acquire certain assets of Vantus Bank, a full service thrift headquartered in Sioux City, Iowa. The related loss sharing agreement was terminated early, effective April 26, 2016, by mutual agreement of Great Southern Bank and the FDIC. Based upon the acquisition date fair values of the net assets acquired, no goodwill was recorded. On October 7, 2011, Great Southern Bank entered into a purchase and assumption agreement with loss share with the FDIC to assume all of the deposits and acquire certain assets of Sun Security Bank, a full service bank headquartered in Ellington, Missouri. The related loss sharing agreement was terminated early, effective April 26, 2016, by mutual agreement of Great Southern Bank and the FDIC. Based upon the acquisition date fair values of the net assets acquired, no goodwill was recorded. On April 27, 2012, Great Southern Bank entered into a purchase and assumption agreement with loss share with the FDIC to assume all of the deposits and acquire certain assets of Inter Savings Bank, FSB (“InterBank”), a full service bank headquartered in Maple Grove, Minnesota. The related loss sharing agreement was terminated early, effective June 9, 2017, by mutual agreement of Great Southern Bank and the FDIC. Based upon the acquisition date fair values of the net assets acquired, no goodwill was recorded. On June 20, 2014, Great Southern Bank entered into a purchase and assumption agreement with the FDIC to purchase a substantial portion of the loans and investment securities, as well as certain other assets, and assume all of the deposits, as well as certain other liabilities, of Valley Bank, a full-service bank headquartered in Moline, Illinois, with significant operations in Iowa. This transaction did not include a loss sharing agreement. Based upon the acquisition date fair values of the net assets acquired, no goodwill was recorded. The following table presents the balances of the acquired loans related to the various FDIC-assisted transactions at December 31, 2020 and December 31, 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sun Security ​ ​ ​ ​ ​ ​ ​ TeamBank Vantus Bank Bank InterBank Valley Bank ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross loans receivable ​ $ 5,393 ​ $ 8,052 ​ $ 13,395 ​ $ 44,215 ​ $ 31,515 Balance of accretable discount due to change in expected losses ​ (97) ​ (35) ​ (180) ​ (1,079) ​ (612) Net carrying value of loans receivable ​ (5,266) ​ (8,004) ​ (13,111) ​ (42,057) ​ (30,204) Expected loss remaining ​ $ 30 ​ $ 13 ​ $ 104 ​ $ 1,079 ​ $ 699 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Gross loans receivable ​ $ 7,304 ​ $ 9,899 ​ $ 17,906 ​ $ 60,430 ​ $ 41,032 Balance of accretable discount due to change in expected losses ​ (159) ​ (89) ​ (374) ​ (5,143) ​ (1,803) Net carrying value of loans receivable ​ (7,118) ​ (9,797) ​ (17,392) ​ (54,442) ​ (38,452) Expected loss remaining ​ $ 27 ​ $ 13 ​ $ 140 ​ $ 845 ​ $ 777 ​ Fair Value and Expected Cash Flows At the time of these acquisitions, the Company determined the fair value of the loan portfolios based on several assumptions. Factors considered in the valuations were projected cash flows for the loans, type of loan and related collateral, classification status, fixed or variable interest rate, term of loan, current discount rates and whether or not the loan was amortizing. Loans were grouped together according to similar characteristics and were treated in the aggregate when applying various valuation techniques. Management also estimated the amount of credit losses that were expected to be realized for the loan portfolios. The discounted cash flow approach was used to value each pool of loans. For non-performing loans, fair value was estimated by calculating the present value of the recoverable cash flows using a discount rate based on comparable corporate bond rates. This valuation of the acquired loans is a significant component leading to the valuation of the loss sharing assets recorded. The amount of the estimated cash flows expected to be received from the acquired loan pools in excess of the fair values recorded for the loan pools is referred to as the accretable yield. The accretable yield is recognized as interest income over the estimated lives of the loans. On an ongoing basis, the Company has evaluated the fair value of the loans including cash flows expected to be collected. Increases in the Company’s cash flow expectations are recognized as increases to the accretable yield while decreases are recognized as impairments through the allowance for loan losses. Improvements in expected cash flows related to the acquired loan portfolios have resulted in adjustments to the accretable yield to be spread over the estimated remaining lives of the loans on a level-yield basis. The amounts of these adjustments during the years ended December 31, 2020, 2019, and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Increase in accretable yield due to increased cash flow expectations ​ $ — ​ $ 12,323 ​ $ 5,202 ​ The adjustments, along with those made in previous years, impacted the Company’s Consolidated Statements of Income as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income and net impact to pre-tax income ​ $ 5,574 ​ $ 7,431 ​ $ 5,134 ​ On an on-going basis the Company has estimated the cash flows expected to be collected from the acquired loan pools. For each of the loan portfolios acquired, the cash flow estimates have increased, based on payment histories and reduced credit loss expectations. This resulted in increased income that has been spread, on a level-yield basis, over the remaining expected lives of the loan pools (and, therefore, has decreased over time). Because these adjustments to accretable yield will be recognized generally over the remaining lives of the loan pools, they will impact future periods as well. As of December 31, 2020, the remaining accretable yield adjustment that will affect interest income was $2.0 million. Of the remaining adjustments affecting interest income, we expect to recognize $1.5 million of interest income during 2021. As of January 1, 2021, we have adopted the new accounting standard related to accounting for credit losses. With the adoption of this standard, there will be no further reclassification of discounts from non-accretable to accretable subsequent to December 31, 2020. All adjustments made prior to January 1, 2021 will continue to be accreted to interest income. Changes in the accretable yield for acquired loan pools were as follows for the years ended December 31, 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sun ​ ​ ​ ​ ​ ​ ​ TeamBank Vantus Bank Security Bank InterBank Valley Bank ​ ​ (In Thousands) Balance, January 1, 2018 ​ ​ 2,071 ​ ​ 1,850 ​ ​ 2,901 ​ ​ 5,074 ​ ​ 2,695 Accretion ​ (1,042) ​ (1,196) ​ (1,667) ​ (8,349) ​ (3,892) Reclassification from nonaccretable difference (1) ​ 327 ​ 778 ​ 1,008 ​ 8,269 ​ 4,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ 1,356 ​ 1,432 ​ 2,242 ​ 4,994 ​ 3,063 Accretion ​ (955) ​ (1,006) ​ (1,562) ​ (8,798) ​ (4,302) Reclassification from nonaccretable difference (1) ​ 756 ​ 697 ​ 1,268 ​ 12,081 ​ 5,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 ​ $ 1,157 ​ $ 1,123 ​ $ 1,948 ​ $ 8,277 ​ $ 4,578 Accretion ​ (479) ​ (831) ​ (1,046) ​ (6,791) ​ (3,005) Reclassification from nonaccretable difference (1) ​ 198 ​ 451 ​ 493 ​ 2,219 ​ 2,764 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 ​ $ 876 ​ $ 743 ​ $ 1,395 ​ $ 3,705 ​ $ 4,337 (1) Represents increases in estimated cash flows expected to be received from the acquired loan pools, primarily due to lower estimated credit losses. The numbers also include changes in expected accretion of the loan pools for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2020, totaling $198,000, $451,000, $493,000, $2.2 million and $2.8 million, respectively; TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2019, totaling $667,000, $480,000, $810,000, $3.9 million and $2.5 million, respectively; for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2018, totaling $312,000, $778,000, $756,000, $4.1 million and $3.5 million, respectively .

Other Real Estate Owned and Rep

Other Real Estate Owned and Repossessions	12 Months Ended
	Dec. 31, 2019
Other Real Estate Owned and Repossessions
Other Real Estate Owned and Repossessions	Note 5: Other Real Estate Owned and Repossessions Major classifications of other real estate owned at December 31, 2020 and 2019, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) Foreclosed assets held for sale and repossessions ​ ​ One- to four-family construction ​ $ — ​ $ — Subdivision construction ​ 263 ​ 689 Land development ​ 250 ​ 1,816 Commercial construction ​ — ​ — One- to four-family residential ​ 111 ​ 601 Other residential ​ — ​ — Commercial real estate ​ — ​ — Commercial business ​ — ​ — Consumer ​ 153 ​ 545 ​ ​ 777 ​ 3,651 ​ ​ ​ ​ ​ Foreclosed assets related to FDIC acquisitions, net of discounts ​ 446 ​ 1,003 ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale and repossessions, net ​ 1,223 ​ 4,654 ​ ​ ​ ​ ​ ​ ​ Other real estate owned not acquired through foreclosure ​ 654 ​ 871 ​ ​ ​ ​ ​ ​ ​ Other real estate owned and repossessions ​ $ 1,877 ​ $ 5,525 ​ At December 31, 2020, other real estate owned not acquired through foreclosure included seven properties all of which were branch locations that were closed and held for sale. During the year ended December 31, 2020, one former branch location was added to this category for $80,000 and was under contract at December 31, 2020. The sale was completed in February 2021, resulting in a small gain. During the year ended December 31, 2020, valuation write-downs of $286,000 were recorded on branch locations that were closed and held for sale. At December 31, 2019, other real estate owned not acquired through foreclosure included six properties all of which were branch locations that were closed and held for sale. During the year ended December 31, 2019, one former branch location was both added to this category and sold at a gain of $115,000, which is included in the net gains on sales of other real estate owned and repossessions amount in the table below. At December 31, 2020, residential mortgage loans totaling $602,000 were in the process of foreclosure, $518,000 of which were acquired loans related to FDIC-assisted transactions. At December 31, 2019, residential mortgage loans totaling $1.6 million were in the process of foreclosure, $1.4 million of which were acquired loans related to FDIC-assisted transactions. Expenses applicable to other real estate owned and repossessions for the years ended December 31, 2020, 2019 and 2018, included the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net gains on sales of other real estate owned and repossessions ​ $ (480) ​ $ (750) ​ $ (2,522) Valuation write-downs ​ 1,320 ​ 926 ​ 3,897 Operating expenses, net of rental income ​ 1,183 ​ 2,008 ​ 3,544 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,023 ​ $ 2,184 ​ $ 4,919 ​

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2020
Premises and Equipment
Premises and Equipment	Note 6: Premises and Equipment Major classifications of premises and equipment at December 31, 2020 and 2019, stated at cost, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Land ​ $ 40,652 ​ $ 40,632 Buildings and improvements ​ 100,187 ​ 96,959 Furniture, fixtures and equipment ​ 59,226 ​ 56,986 Operating leases right of use asset ​ 8,536 ​ 8,668 ​ ​ 208,601 ​ 203,245 Less accumulated depreciation ​ 69,431 ​ 61,337 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 139,170 ​ $ 141,908 ​ Leases. Leases (Topic 842) All of our leases are classified as operating leases (as they were prior to January 1, 2019), and therefore were previously not recognized on the Company’s consolidated statements of financial condition. With the adoption of ASU 2016-02, these operating leases are now included as a right of use asset in the premises and equipment line item on the Company’s consolidated statements of financial condition. The corresponding lease liability is included in the accrued expenses and other liabilities line item on the Company’s consolidated statements of financial condition. Because these leases are classified as operating leases, the adoption of the new standard did not have a material effect on lease expense on the Company’s consolidated statements of income. ASU 2016-02 provides a number of optional practical expedients in transition. The Company has elected the “package of practical expedients,” which permits the Company not to reassess under the new standard the prior conclusions about lease identification, lease classification and initial direct costs. The Company also elected the use of hindsight, a practical expedient which permits the use of information available after lease inception to determine the lease term via the knowledge of renewal options exercised not available as of the lease’s inception. The practical expedient pertaining to land easements is not applicable to the Company. ASU 2016-02 also requires certain other accounting elections. The Company elected the short-term lease recognition exemption for all leases that qualify, meaning those with terms under twelve months. Right of use assets or lease liabilities are not to be recognized for short-term leases. The Company also elected the practical expedient to not separate lease and non-lease components for all leases. The Company’s short-term leases related to offsite ATMs have both fixed and variable lease payment components, based on the number of transactions at the various ATMs. The variable portion of these lease payments is not material and the total lease expense related to ATMs was $ 275,000 and $ 286,000 for the years ended December 31, 2020 and December 31, 2019, respectively. The calculated amounts of the right of use assets and lease liabilities in the table below are impacted by the length of the lease term and the discount rate used to present value the minimum lease payments. The Company’s lease agreements often include one or more options to renew extended term in the calculation of the right of use asset and lease liability. Regarding the discount rate, the ASU requires the use of the rate implicit in the lease at the Company’s discretion. If at lease inception, the Company considers the exercising of a renewal option to be reasonably certain, the Company will include the extended term in the calculation of the right of use asset and lease liability. Regarding the discount rate, the ASU requires the use of the rate implicit in the lease whenever this rate is readily determinable. As this rate is rarely determinable, the Company utilizes its incremental borrowing rate at lease inception over a similar term. The discount rate utilized was the FHLBank borrowing rate for the term corresponding to the expected term of the lease. The expected lease terms range from 0.8 years to 17.9 years with a weighted-average lease term of 8.3 years. The weighted-average discount rate was 3.24%. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At or For the Year Ended ​ ​ December 31, 2020 December 31, 2019 ​ ​ (In Thousands) Statement of Financial Condition ​ ​ ​ ​ Operating leases right of use asset ​ $ 8,536 ​ $ 8,668 Operating leases liability ​ $ 8,661 ​ $ 8,747 ​ ​ ​ ​ ​ ​ ​ Statement of Income ​ ​ ​ Operating lease costs classified as occupancy and equipment expense ​ $ 1,572 ​ $ 1,460 (includes short-term lease costs and amortization of right of use asset) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental Cash Flow Information ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ Operating cash flows from operating leases ​ $ 1,526 ​ $ 1,381 Right of use assets obtained in exchange for lease obligations: ​ ​ ​ Operating leases ​ $ 972 ​ $ 9,538 ​ For the years ended December 31, 2020 and 2019, lease expense was $1.6 million and $1.5 million, respectively. At December 31, 2020, future expected lease payments for leases with terms exceeding one year were as follows (in thousands): ​ ​ ​ ​ ​ 2021 $ 1,119 2022 ​ 1,116 2023 ​ 1,088 2024 ​ 1,005 2025 ​ 979 Thereafter ​ 4,926 ​ ​ ​ ​ Future lease payments expected ​ 10,233 ​ ​ ​ ​ Less interest portion of lease payments ​ (1,572) ​ ​ ​ ​ Lease liability ​ $ 8,661 ​ The Company does not sublease any of its leased facilities; however, it does lease to other third parties portions of facilities that it owns. In terms of being the lessor in these circumstances, all of these lease agreements are classified as operating leases. In the years ended December 31, 2020 and 2019, income recognized from these lease agreements was $1.2 million and $1.1 million, respectively, and was included in occupancy and equipment expense.

Investments in Limited Partners

Investments in Limited Partnerships	12 Months Ended
	Dec. 31, 2020
Investments in Limited Partnerships
Investments in Limited Partnerships	Note 7: Investments in Limited Partnerships Investments in Affordable Housing Partnerships The Company has invested in certain limited partnerships that were formed to develop and operate apartments and single-family houses designed as high-quality affordable housing for lower income tenants throughout Missouri and contiguous states. At December 31, 2020 the Company had 16 such investments, with a net carrying value of $20.4 million. At December 31, 2019 the Company had 15 such investments, with a net carrying value of $22.8 million. Due to the Company’s inability to exercise any significant influence over any of the investments in Affordable Housing Partnerships, they all are accounted for using the proportional amortization method. Each of the partnerships must meet the regulatory requirements for affordable housing for a minimum 15-year compliance period to fully utilize the tax credits. If the partnerships cease to qualify during the compliance period, the credits may be denied for any period in which the projects are not in compliance and a portion of the credits previously taken may be subject to recapture with interest. The remaining federal affordable housing tax credits to be utilized through 2030 were $22.1 million as of December 31, 2020, assuming no tax credit recapture events occur and all projects currently under construction are completed as planned. Amortization of the investments in partnerships is expected to be approximately $20.4 million, assuming all projects currently under construction are completed and funded as planned. The Company’s usage of federal affordable housing tax credits approximated $6.6 million, $8.0 million and $6.6 million during 2020, 2019 and 2018, respectively. Investment amortization amounted to $5.5 million, $5.8 million and $5.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. Investments in Community Development Entities The Company has invested in certain limited partnerships that were formed to develop and operate business and real estate projects located in low-income communities. At December 31, 2020 the Company had one such investment, with a net carrying value of $567,000 . At December 31, 2019, the Company had no such investment. Due to the Company’s inability to exercise any significant influence over any of the investments in qualified Community Development Entities, they are all accounted for using the cost method. Each of the partnerships provides federal New Market Tax Credits over a seven-year credit allowance period. In each of the first three years, credits totaling five percent of the original investment are allowed on the credit allowance dates and for the final four years, credits totaling six percent of the original investment are allowed on the credit allowance dates. Each of the partnerships must be invested in a qualified Community Development Entity on each of the credit allowance dates during the seven-year period to utilize the tax credits. If the Community Development Entities cease to qualify during the seven-year period, the credits may be denied for any credit allowance date and a portion of the credits previously taken may be subject to recapture with interest. The investments in the Community Development Entities cannot be redeemed before the end of the seven-year period. The Company’s usage of federal New Market Tax Credits approximated $100,000, $480,000 and $480,000 during 2020, 2019 and 2018, respectively. Investment amortization amounted to $80,000, $365,000 and $575,000 for the years ended December 31, 2020, 2019 and 2018, respectively. Investments in Limited Partnerships for Federal Rehabilitation/Historic Tax Credits From time to time, the Company has invested in certain limited partnerships that were formed to provide certain federal rehabilitation/historic tax credits. At December 31, 2020 the Company had one such investments, with a net carrying value of $863,000. Previously, the Company utilized these credits in their entirety in the year the project was placed in service and the impact to the Consolidated Statements of Income has not been material. In future periods, such partnerships provide federal rehabilitation/historic tax credits over a five-year credit allowance period. Investments in Limited Partnerships for State Tax Credits From time to time, the Company has invested in certain limited partnerships that were formed to provide certain state tax credits. The Company has primarily syndicated these tax credits and the impact to the Consolidated Statements of Income has not been material.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2020
Deposits
Deposits	Note 8: Deposits Deposits at December 31, 2020 and 2019, are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Interest Rate 2020 2019 ​ ​ ​ ​ (In Thousands, Except Interest Rates) ​ ​ ​ ​ ​ ​ ​ ​ ​ Noninterest-bearing accounts — ​ $ 984,798 ​ $ 687,068 Interest-bearing checking and savings accounts 0.22% and 0.55% 2,141,313 ​ 1,551,929 ​ ​ ​ 3,126,111 ​ ​ 2,238,997 ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificate accounts 0% - 0.99% ​ 803,737 ​ 122,649 ​ 1% - 1.99% ​ 425,061 ​ 523,816 ​ 2% - 2.99% ​ 143,417 ​ 1,053,914 ​ 3% - 3.99% ​ 18,148 ​ 19,849 ​ 4% and above ​ 429 ​ 881 ​ ​ ​ 1,390,792 ​ ​ 1,721,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 4,516,903 ​ $ 3,960,106 ​ The weighted average interest rate on certificates of deposit was 1.00% and 2.09% at December 31, 2020 and 2019, respectively. The aggregate amount of certificates of deposit originated by the Bank in denominations greater than $250,000 was approximately $123.1 million and $153.1 million at December 31, 2020 and 2019, respectively. The aggregate amount of certificates of deposit originated by the Bank in denominations greater than $100,000 was approximately $762.9 million and $830.8 million at December 31, 2020 and 2019, respectively. The Bank utilizes brokered deposits as an additional funding source. The aggregate amount of brokered deposits was approximately $158.7 million and $371.7 million at December 31, 2020 and 2019, respectively. At December 31, 2020, scheduled maturities of certificates of deposit were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail Brokered Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 995,934 ​ $ 91,345 ​ $ 1,087,279 2022 ​ 175,913 ​ 13,751 ​ 189,664 2023 ​ 30,898 ​ 42,448 ​ 73,346 2024 ​ 14,647 ​ 11,200 ​ 25,847 2025 ​ 13,743 ​ — ​ 13,743 Thereafter ​ 913 ​ — ​ 913 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,232,048 ​ $ 158,744 ​ $ 1,390,792 ​ A summary of interest expense on deposits for the years ended December 31, 2020, 2019 and 2018, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Checking and savings accounts ​ $ 7,096 ​ $ 7,971 ​ $ 5,982 Certificate accounts ​ 25,453 ​ 37,723 ​ 22,149 Early withdrawal penalties ​ (118) ​ (124) ​ (174) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 32,431 ​ $ 45,570 ​ $ 27,957 ​

Advances From Federal Home Loan

Advances From Federal Home Loan Bank	12 Months Ended
	Dec. 31, 2020
Advances From Federal Home Loan Bank
Advances From Federal Home Loan Bank	Note 9: Advances From Federal Home Loan Bank At December 31, 2020 and 2019, there were no outstanding term advances from the Federal Home Loan Bank of Des Moines. At December 31, 2019, there were overnight funds from the Federal Home Loan Bank of Des Moines, which are included below in Note 10 The Bank has pledged FHLB stock, investment securities and first mortgage loans free of other pledges, liens and encumbrances as collateral for outstanding advances. No investment securities were specifically pledged as collateral for advances at December 31, 2020 and 2019. Loans with carrying values of approximately $1.63 billion and $1.60 billion were pledged as collateral for outstanding advances at December 31, 2020 and 2019, respectively. The Bank had potentially available $1.07 billion remaining on its line of credit under a borrowing arrangement with the FHLB of Des Moines at December 31, 2020.

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2020
Short-Term Borrowings
Short-Term Borrowings	Note 10: Short-Term Borrowings Short-term borrowings at December 31, 2020 and 2019, are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Notes payable – Community Development Equity Funds ​ $ 1,518 ​ $ 1,267 Other interest-bearing liabilities ​ — ​ 30,890 Overnight borrowings from the Federal Home Loan Bank ​ — ​ 196,000 Securities sold under reverse repurchase agreements ​ 164,174 ​ 84,167 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 165,692 ​ $ 312,324 ​ The Bank enters into sales of securities under agreements to repurchase (reverse repurchase agreements). Reverse repurchase agreements are treated as financings, and the obligations to repurchase securities sold are reflected as a liability in the statements of financial condition. The dollar amount of securities underlying the agreements remains in the asset accounts. Securities underlying the agreements are being held by the Bank during the agreement period. All agreements are written on a term of one-month or less. At December 31, 2019, other interest-bearing liabilities consisted of cash collateral held by the Company to satisfy minimum collateral posting thresholds with its derivative dealer counterparties representing the termination value of derivatives, which at such time were in a net asset position. Under the collateral agreements between the parties, either party may choose to provide cash or securities to satisfy its collateral requirements. Short-term borrowings had weighted average interest rates of 0.02% and 1.25 % at December 31, 2020 and 2019, respectively. Short-term borrowings averaged approximately $183.5 million and $260.0 million for the years ended December 31, 2020 and 2019, respectively. The maximum amounts outstanding at any month end were $318.7 million and $346.9 million, respectively, during those same periods. The following table represents the Company’s securities sold under reverse repurchase agreements, by collateral type and remaining contractual maturity at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ Overnight and ​ Overnight and ​ ​ Continuous ​ Continuous ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Mortgage-backed securities – GNMA, FNMA, FHLMC ​ $ 164,174 ​ $ 84,167 ​

Federal Reserve Bank Borrowings

Federal Reserve Bank Borrowings	12 Months Ended
	Dec. 31, 2020
Federal Reserve Bank Borrowings
Federal Reserve Bank Borrowings	Note 11: Federal Reserve Bank Borrowings At December 31, 2020 and 2019, the Bank had $436.4 million and $367.8 million, respectively, available under a line-of-credit borrowing arrangement with the Federal Reserve Bank. The line is secured primarily by consumer and commercial loans. There were no amounts borrowed under this arrangement at December 31, 2020 or 2019.

Subordinated Debentures Issued

Subordinated Debentures Issued to Capital Trusts	12 Months Ended
	Dec. 31, 2020
Subordinated Debentures Issued to Capital Trusts
Subordinated Debentures Issued to Capital Trusts	Note 12: Subordinated Debentures Issued to Capital Trusts In November 2006, Great Southern Capital Trust II (Trust II), a statutory trust formed by the Company for the purpose of issuing the securities, issued a $25.0 million aggregate liquidation amount of floating rate cumulative trust preferred securities. The Trust II securities bear a floating distribution rate equal to 90-day LIBOR plus 1.60 %. The Trust II securities became redeemable at the Company’s option in February 2012, and if not sooner redeemed, mature on February 1, 2037. The Trust II securities were sold in a private transaction exempt from registration under the Securities Act of 1933, as amended. The gross proceeds of the offering were used to purchase Junior Subordinated Debentures from the Company totaling $25.8 million and bearing an interest rate identical to the distribution rate on the Trust II securities. The initial interest rate on the Trust II debentures was 6.98 %. The interest rate was 1.81% and 3.51% at December 31, 2020 and 2019, respectively. At December 31, 2020 and 2019, subordinated debentures issued to capital trusts are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Subordinated debentures ​ $ 25,774 $ 25,774 ​

Subordinated Notes

Subordinated Notes	12 Months Ended
	Dec. 31, 2020
Subordinated Notes
Subordinated Notes	Note 13: Subordinated Notes On August 8, 2016, the Company completed the public offering and sale of $75.0 million of its subordinated notes. The notes are due August 15, 2026, and have a fixed interest rate of 5.25% until August 15, 2021, at which time the rate becomes floating at a rate equal to three-month LIBOR plus 4.087%. The Company may call the notes at par beginning on August 15, 2021, and on any scheduled interest payment date thereafter. The notes were sold at par, resulting in net proceeds, after underwriting discounts and commissions, legal, accounting and other professional fees, of approximately $73.5 million. Total debt issuance costs of approximately $1.5 million were deferred and are being amortized over the expected life of the notes, which is five years . On June 10, 2020, the Company completed the public offering and sale of $75.0 million of its subordinated notes. The notes are due June 15, 2030, and have a fixed interest rate of 5.50% until June 15, 2025, at which time the rate becomes floating at a rate expected to be equal to three-month term Secured Overnight Financing Rate (SOFR) plus 5.325% . The Company may call the notes at par beginning on June 15, 2025, and on any scheduled interest payment date thereafter. The notes were sold at par, resulting in net proceeds, after underwriting discounts and commissions, legal, accounting and other professional fees, of approximately $73.5 million. Total debt issuance costs of approximately $1.5 million were deferred and are being amortized over the expected life of the notes, which is five years . Amortization of the debt issuance costs during the years ended December 31, 2020 and 2019, totaled $608,000 and $434,000, respectively, and is included in interest expense on subordinated notes in the consolidated statements of income, resulting in an imputed interest rate of 5.84 % and 5.89%, respectively. At December 31, 2020 and 2019, subordinated notes are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Subordinated notes ​ $ 150,000 ​ $ 75,000 Less: unamortized debt issuance costs ​ 1,603 ​ 724 ​ ​ $ 148,397 ​ $ 74,276 ​

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Taxes
Income Taxes	Note 14: Income Taxes The Company files a consolidated federal income tax return. As of December 31, 2020 and 2019, retained earnings included approximately $17.5 million for which no deferred income tax liability had been recognized. This amount represents an allocation of income to bad debt deductions for tax purposes only for tax years prior to 1988. If the Bank were to liquidate, the entire amount would have to be recaptured and would create income for tax purposes only, which would be subject to the then-current corporate income tax rate. The unrecorded deferred income tax liability on the above amount was approximately $3.9 million at both December 31, 2020 and 2019, respectively. During the years ended December 31, 2020, 2019 and 2018, the provision for income taxes included these components: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Taxes currently payable ​ $ 25,259 ​ $ 15,375 ​ $ 19,291 Deferred income taxes (benefit) ​ (11,480) ​ 1,074 ​ (4,450) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income taxes ​ $ 13,779 ​ $ 16,449 ​ $ 14,841 ​ The tax effects of temporary differences related to deferred taxes shown on the statements of financial condition were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (In Thousands) Deferred tax assets ​ ​ Allowance for loan losses ​ $ 12,711 ​ $ 9,188 Interest on nonperforming loans ​ 142 ​ 161 Accrued expenses ​ 894 ​ 821 Write-down of foreclosed assets ​ 131 ​ 185 Write-down of fixed assets ​ 114 ​ 50 Income recognized for tax in excess of book ​ 8,830 ​ — Partnership tax credits ​ 11 ​ 732 Deferred income ​ 885 ​ 509 Difference in basis for acquired assets and liabilities ​ ​ 1,532 ​ ​ 2,540 ​ ​ 25,250 ​ 14,186 ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities ​ ​ Tax depreciation in excess of book depreciation ​ (5,988) ​ (5,986) FHLB stock dividends ​ (368) ​ (817) Prepaid expenses ​ (898) ​ (891) Unrealized gain on available-for-sale securities ​ (6,869) ​ (2,671) Unrealized gain on cash flow derivatives ​ (8,830) ​ (6,853) Other ​ (258) ​ (233) ​ ​ (23,211) ​ (17,451) ​ ​ ​ ​ ​ ​ ​ Net deferred tax asset (liability) ​ $ 2,039 ​ $ (3,265) ​ Reconciliations of the Company’s effective tax rates from continuing operations to the statutory corporate tax rates were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Tax at statutory rate 21.0 % 21.0 % 21.0 % Nontaxable interest and dividends (0.5) (0.5) (0.8) ​ Tax credits (3.8) (3.6) (3.4) ​ State taxes 1.4 1.3 1.1 ​ Other 0.8 0.1 0.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 18.9 % 18.3 % 18.1 % ​ The Company and its consolidated subsidiaries have not been audited recently by the Internal Revenue Service (IRS), except as described here. The Company, through one of its subsidiaries, is a partner in two partnerships which were under IRS examination for 2006 and 2007. As a result, the Company’s 2006 and subsequent tax years remained open for examination. The examinations of these partnerships were completed during 2019. The completion of these examinations did not result in significant changes to the Company’s tax positions. As a result, federal tax years through December 31, 2016 are now closed. The Company is currently under State of Missouri income and franchise tax examinations for its 2014 and 2015 tax years. The Company does not currently expect significant adjustments to its financial statements from this state examination.

Disclosures About Fair Value of

Disclosures About Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Disclosures About Fair Value of Financial Instruments
Disclosures About Fair Value of Financial Instruments	Note 15: Disclosures About Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurements ● Quoted prices in active markets for identical assets or liabilities (Level 1): Inputs that are quoted unadjusted prices in active markets for identical assets that the Company has the ability to access at the measurement date. An active market for the asset is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. ● Other observable inputs (Level 2): Inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the reporting entity including quoted prices for similar assets, quoted prices for securities in inactive markets and inputs derived principally from or corroborated by observable market data by correlation or other means. ● Significant unobservable inputs (Level 3): Inputs that reflect assumptions of a source independent of the reporting entity or the reporting entity’s own assumptions that are supported by little or no market activity or observable inputs. Financial instruments are broken down by recurring or nonrecurring measurement status. Recurring assets are initially measured at fair value and are required to be remeasured at fair value in the financial statements at each reporting date. Assets measured on a nonrecurring basis are assets that, due to an event or circumstance, were required to be remeasured at fair value after initial recognition in the financial statements at some time during the reporting period. The Company considers transfers between the levels of the hierarchy to be recognized at the end of related reporting periods. Recurring Measurements The following table presents the fair value measurements of assets recognized in the accompanying balance sheets measured at fair value on a recurring basis and the level within the fair value hierarchy in which the fair value measurements fall at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Markets ​ Other ​ Significant ​ ​ ​ ​ ​ for Identical ​ Observable ​ Unobservable ​ ​ ​ Assets Inputs ​ Inputs ​ Fair Value (Level 1) (Level 2) (Level 3) ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 169,940 ​ $ — ​ $ 169,940 ​ $ — Agency collateralized mortgage obligations ​ 176,621 ​ — ​ 176,621 ​ — States and political subdivisions securities ​ 47,325 ​ — ​ 47,325 ​ — Small Business Administration securities ​ 21,047 ​ — ​ 21,047 ​ — Interest rate derivative asset ​ 5,062 ​ — ​ 5,062 ​ — Interest rate derivative liability ​ (5,454) ​ — ​ (5,454) ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 165,042 ​ $ — ​ $ 165,042 ​ $ — Agency collateralized mortgage obligations ​ 151,950 ​ — ​ 151,950 ​ — States and political subdivisions securities ​ ​ 35,125 ​ ​ — ​ ​ 35,125 ​ ​ — Small Business Administration securities ​ 22,058 ​ — ​ 22,058 ​ — Interest rate derivative asset ​ 31,476 ​ — ​ 31,476 ​ — Interest rate derivative liability ​ (1,547) ​ — ​ (1,547) ​ — ​ The following is a description of inputs and valuation methodologies used for assets recorded at fair value on a recurring basis and recognized in the accompanying statements of financial condition at December 31, 2020 and 2019, as well as the general classification of such assets pursuant to the valuation hierarchy. There have been no significant changes in the valuation techniques during the year ended December 31, 2020. Available-for-Sale Securities Investment securities available for sale are recorded at fair value on a recurring basis. The fair values used by the Company are obtained from an independent pricing service, which represent either quoted market prices for the identical asset or fair values determined by pricing models, or other model-based valuation techniques, that consider observable market data, such as interest rate volatilities, LIBOR yield curve, credit spreads and prices from market makers and live trading systems. Recurring Level 1 securities include exchange traded equity securities. There were no recurring Level 1 securities at December 31, 2020 or 2019. Recurring Level 2 securities include U.S. government agency securities, mortgage-backed securities, state and municipal bonds and certain other investments. Inputs used for valuing Level 2 securities include observable data that may include dealer quotes, benchmark yields, market spreads, live trading levels and market consensus prepayment speeds, among other things. Additional inputs include indicative values derived from the independent pricing service’s proprietary computerized models. There were no recurring Level 3 securities at December 31, 2020 or 2019. Interest Rate Derivatives The fair value is estimated using forward-looking interest rate curves and is determined using observable market rates and, therefore, are classified within Level 2 of the valuation hierarchy. Nonrecurring Measurements The following tables present the fair value measurement of assets measured at fair value on a nonrecurring basis and the level within the fair value hierarchy in which the fair value measurements fall at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Markets ​ Other ​ Significant ​ ​ ​ for Identical ​ Observable ​ Unobservable ​ ​ ​ Assets Inputs ​ Inputs ​ Fair Value (Level 1) (Level 2) (Level 3) ​ (In Thousands) December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 1,759 ​ $ — ​ $ — ​ $ 1,759 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale ​ $ 945 ​ $ — ​ $ — ​ $ 945 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 635 ​ $ — ​ $ — ​ $ 635 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale ​ $ 1,112 ​ $ — ​ $ — ​ $ 1,112 ​ Following is a description of the valuation methodologies used for assets measured at fair value on a nonrecurring basis and recognized in the accompanying statements of financial condition, as well as the general classification of such assets pursuant to the valuation hierarchy. For assets classified within Level 3 of the fair value hierarchy, the process used to develop the reported fair value is described below. Loans Held for Sale Mortgage loans held for sale are recorded at the lower of carrying value or fair value. The fair value of mortgage loans held for sale is based on what secondary markets are currently offering for portfolios with similar characteristics. As such, the Company classifies mortgage loans held for sale as Nonrecurring Level 2. Write-downs to fair value typically do not occur as the Company generally enters into commitments to sell individual mortgage loans at the time the loan is originated to reduce market risk. The Company typically does not have commercial loans held for sale. At December 31, 2020 and 2019, the aggregate fair value of mortgage loans held for sale exceeded their cost. Accordingly, no mortgage loans held for sale were marked down and reported at fair value. Impaired Loans A loan is considered to be impaired when it is probable that all of the principal and interest due may not be collected according to its contractual terms. Generally, when a loan is considered impaired, the amount of reserve required under FASB ASC 310, Receivables The Company records impaired loans as Nonrecurring Level 3. If a loan’s fair value as estimated by the Company is less than its carrying value, the Company either records a charge-off for the portion of the loan that exceeds the fair value or establishes a reserve within the allowance for loan losses specific to the loan. Loans for which such charge-offs or reserves were recorded during the years ended December 31, 2020 and 2019, are shown in the table above (net of reserves). Foreclosed Assets Held for Sale Foreclosed assets held for sale are initially recorded at fair value less estimated cost to sell at the date of foreclosure. Subsequent to foreclosure, valuations are periodically performed by management and the assets are carried at the lower of carrying amount or fair value less estimated cost to sell. Foreclosed assets held for sale are classified within Level 3 of the fair value hierarchy. The foreclosed assets represented in the table above have been re-measured during the years ended December 31, 2020 and 2019, subsequent to their initial transfer to foreclosed assets. Fair Value of Financial Instruments The following methods were used to estimate the fair value of all other financial instruments recognized in the accompanying statements of financial condition at amounts other than fair value. Cash and Cash Equivalents and Federal Home Loan Bank Stock The carrying amount approximates fair value. Loans and Interest Receivable The fair value of loans is estimated on an exit price basis incorporating contractual cash flow, prepayments discount spreads, credit loss and liquidity premiums. Loans with similar characteristics are aggregated for purposes of the calculations. The carrying amount of accrued interest receivable approximates its fair value. Deposits and Accrued Interest Payable The fair value of demand deposits and savings accounts is the amount payable on demand at the reporting date, i.e., their carrying amounts. The fair value of fixed maturity certificates of deposit is estimated using a discounted cash flow calculation using the average advances yield curve from 11 districts of the FHLB for the as of date. Federal Home Loan Bank Advances Rates currently available to the Company for debt with similar terms and remaining maturities are used to estimate fair value of existing advances. Short-Term Borrowings The carrying amount approximates fair value. Subordinated Debentures Issued to Capital Trusts The subordinated debentures have floating rates that reset quarterly. The carrying amount of these debentures approximates their fair value. Subordinated Notes The fair values used by the Company are obtained from independent sources and are derived from quoted market prices of the Company’s subordinated notes and quoted market prices of other subordinated debt instruments with similar characteristics. Commitments to Originate Loans, Letters of Credit and Lines of Credit The fair value of commitments is estimated using the fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the present creditworthiness of the counterparties. For fixed rate loan commitments, fair value also considers the difference between current levels of interest rates and the committed rates. The fair value of letters of credit is based on fees currently charged for similar agreements or on the estimated cost to terminate them or otherwise settle the obligations with the counterparties at the reporting date. The following table presents estimated fair values of the Company’s financial instruments. The fair values of certain of these instruments were calculated by discounting expected cash flows, which method involves significant judgments by management and uncertainties. Fair value is the estimated amount at which financial assets or liabilities could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale. Because no market exists for certain of these financial instruments and because management does not intend to sell these financial instruments, the Company does not know whether the fair values shown below represent values at which the respective financial instruments could be sold individually or in the aggregate. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ Carrying ​ Fair ​ Hierarchy ​ Carrying ​ Fair ​ Hierarchy ​ Amount Value Level Amount Value Level ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 563,729 ​ $ 563,729 1 ​ $ 220,155 ​ $ 220,155 1 Mortgage loans held for sale ​ 17,780 ​ 17,780 2 ​ 9,242 ​ 9,242 2 Loans, net of allowance for loan losses ​ 4,296,804 ​ 4,303,909 3 ​ 4,153,982 ​ 4,129,984 3 Accrued interest receivable ​ 12,793 ​ 12,793 3 ​ 13,530 ​ 13,530 3 Investment in FHLB stock and other assets ​ 9,806 ​ 9,806 3 ​ 13,473 ​ 13,473 3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deposits ​ 4,516,903 ​ 4,523,586 3 ​ 3,960,106 ​ 3,963,875 3 Short-term borrowings ​ 165,692 ​ 165,692 3 ​ 312,324 ​ 312,324 3 Subordinated debentures ​ 25,774 ​ 25,774 3 ​ 25,774 ​ 25,774 3 Subordinated notes ​ 148,397 ​ 157,032 2 ​ 74,276 ​ 76,875 2 Accrued interest payable ​ 2,594 ​ 2,594 3 ​ 4,250 ​ 4,250 3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized financial instruments (net of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commitments to originate loans ​ — ​ — 3 ​ — ​ — 3 Letters of credit ​ 84 ​ 84 3 ​ 109 ​ 109 3 Lines of credit ​ — ​ — 3 ​ — ​ — 3 ​

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
	Dec. 31, 2020
Derivatives and Hedging Activities
Derivatives and Hedging Activities	Note 16: Derivatives and Hedging Activities Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity and credit risk, primarily by managing the amount, sources and duration of its assets and liabilities. In the normal course of business, the Company may use derivative financial instruments (primarily interest rate swaps) from time to time to assist in its interest rate risk management. The Company has interest rate derivatives that result from a service provided to certain qualifying loan customers that are not used to manage interest rate risk in the Company’s assets or liabilities and are not designated in a qualifying hedging relationship. The Company manages a matched book with respect to its derivative instruments in order to minimize its net risk exposure resulting from such transactions. In addition, the Company has interest rate derivatives that are designated in a qualified hedging relationship. Nondesignated Hedges The Company has interest rate swaps that are not designated in a qualifying hedging relationship. Derivatives not designated as hedges are not speculative and result from a service the Company provides to certain loan customers. The Company executes interest rate swaps with commercial banking customers to facilitate their respective risk management strategies. Those interest rate swaps are simultaneously hedged by offsetting interest rate swaps that the Company executes with a third party, such that the Company minimizes its net risk exposure resulting from such transactions. As the interest rate swaps associated with this program do not meet the strict hedge accounting requirements, changes in the fair value of both the customer swaps and the offsetting swaps are recognized directly in earnings. As part of the Valley Bank FDIC-assisted acquisition, the Company acquired certain loans with related interest rate swaps. Valley’s swap program differed from the Company’s in that Valley did not have back to back swaps with the customer and a counterparty. The notional amount of the two remaining Valley swaps was $584,000 at December 31, 2020. At December 31, 2020, excluding the Valley Bank swaps, the Company had 19 interest rate swaps totaling $142.8 million in notional amount with commercial customers, and 19 interest rate swaps with the same notional amount with third parties related to its program. In addition, at December 31, 2020, the Company had four participation loans purchased totaling $27.7 million, in which the lead institution has an interest rate swap with their customer and the economics of the counterparty swap are passed along to us through the loan participation. At December 31, 2019, excluding the Valley Bank swaps, the Company had 19 interest rate swaps totaling $96.0 million in notional amount with commercial customers, and 19 interest rate swaps with the same notional amount with third parties related to its program. In addition, at December 31, 2019, the Company had five participation loans purchased totaling $37.4 million, in which the lead institution has an interest rate swap with their customer and the economics of the counterparty swap are passed along to us through the loan participation. During the years ended December 31, 2020, 2019 and 2018, the Company recognized net gains (losses) of $(264,000), $(104,000) and $25,000, respectively, in noninterest income related to changes in the fair value of these swaps. Cash Flow Hedges Interest Rate Swap. million on this interest rate swap during the years ended December 31, 2020 and 2019, respectively. The effective portion of the gain or loss on the derivative is reported as a component of other comprehensive income and reclassified into earnings in the same period or periods during which the hedged transaction affected earnings. Gains and losses on the derivative representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. During each of the years ended December 31, 2020 and 2019, the Company recognized no noninterest income related to changes in the fair value of this derivative. On March 2, 2020, the Company and its swap counterparty mutually agreed to terminate the swap, effective on that date. The Company received a payment of $45.9 million, including accrued but unpaid interest, from its swap counterparty as a result of this termination. This $45.9 million, less the accrued interest portion and net of deferred income taxes, was reflected in the Company’s stockholders’ equity as Accumulated Other Comprehensive Income and a portion of it is being accreted to interest income on loans monthly through the original contractual termination date of October 6, 2025. This has the effect of reducing Accumulated Other Comprehensive Income and increasing Net Interest Income and Retained Earnings over the period. In each quarterly period, commencing with the quarter ended June 30, 2020, until the original contract termination date, the Company expects to record loan interest income related to this swap transaction of approximately $2.0 million, based on the termination value of the swap. The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the Consolidated Statements of Financial Condition: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location in ​ Fair Value ​ ​ Consolidated Statements ​ December 31, ​ December 31, ​ ​ of Financial Condition 2020 2019 ​ ​ ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives designated as hedging instruments ​ ​ ​ Interest rate swap ​ Prepaid expenses and other assets ​ $ — ​ $ 30,056 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivatives designated as hedging instruments ​ ​ ​ $ — ​ $ 30,056 ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets ​ ​ Interest rate products Prepaid expenses and other assets ​ $ 5,062 ​ $ 1,420 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivatives not designated as hedging instruments ​ ​ ​ $ 5,062 ​ $ 1,420 ​ ​ ​ Derivative Liabilities ​ ​ Interest rate products Accrued expenses and other liabilities ​ $ 5,454 ​ $ 1,547 ​ ​ ​ Total derivatives not designated as hedging instruments ​ ​ ​ $ 5,454 ​ $ 1,547 ​ The following table presents the effect of cash flow hedge accounting on the statements of comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Gain ​ ​ Recognized in AOCI ​ ​ Year Ended December 31 Cash Flow Hedges 2020 2019 2018 ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap, net of income taxes ​ $ 6,691 ​ $ 13,857 $ 9,345 ​ The following table presents the effect of cash flow hedge accounting on the statements of operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31 Cash Flow Hedges ​ 2020 ​ 2019 ​ 2018 ​ ​ Interest ​ Interest ​ Interest ​ Interest ​ Interest ​ Interest ​ Income Expense Income ​ Expense ​ Income ​ Expense ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap, net of income taxes ​ $ 7,676 ​ $ — ​ $ 3,082 ​ $ — ​ $ 673 ​ $ — ​ Agreements with Derivative Counterparties The Company has agreements with its derivative counterparties. If the Company defaults on any of its indebtedness, including a default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. If the Bank fails to maintain its status as a well-capitalized institution, then the counterparty could terminate the derivative positions and the Company would be required to settle its obligations under the agreements. Similarly, the Company could be required to settle its obligations under certain of its agreements if certain regulatory events occurred, such as the issuance of a formal directive, or if the Company’s credit rating is downgraded below a specified level. At December 31, 2020, the termination value of derivatives with our derivative dealer counterparties (related to loan level swaps with commercial lending customers) in a net liability position, which included accrued interest but excluded any adjustment for nonperformance risk, related to these agreements was $391,000. Additionally, the Company’s activity with two of its derivative counterparties met the level at which the minimum collateral posting thresholds take effect (collateral to be given by the Company) and the Company had posted collateral of $5.3 million to the derivative counterparties to satisfy the loan level agreements. If the Company had breached any of these provisions at December 31, 2020 or December 31, 2019, it could have been required to settle its obligations under the agreements at the termination value. At December 31, 2019, the termination value of derivatives with our derivative dealer counterparties (related to loan level swaps with commercial lending customers) in a net liability position, which included accrued interest but excluded any adjustment for nonperformance risk, related to these agreements was $1.1 million. At December 31, 2019, other interest-bearing liabilities consisted of cash collateral held by the Company to satisfy minimum collateral posting thresholds with its derivative dealer counterparties representing the termination value of derivatives, which at such time were in a net asset position. Under the collateral agreements between the parties, either party may choose to provide cash or securities to satisfy its collateral requirements. Effective March 2, 2020, the Company and its swap counterparty mutually agreed to terminate the Company’s interest rate swap, eliminating the cash collateral held.

Commitments and Credit Risk

Commitments and Credit Risk	12 Months Ended
	Dec. 31, 2020
Commitments and Credit Risk
Commitments and Credit Risk	Note 17: Commitments and Credit Risk Commitments to Originate Loans Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since a significant portion of the commitments may expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Bank evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Bank upon extension of credit, is based on management’s credit evaluation of the counterparty. Collateral held varies but may include accounts receivable, inventory, property and equipment, commercial real estate and residential real estate. At December 31, 2020 and 2019, the Bank had outstanding commitments to originate loans and fund commercial construction loans aggregating approximately $46.6 million and $92.4 million, respectively. The commitments extend over varying periods of time with the majority being disbursed within a 30- to 180-day period. Mortgage loans in the process of origination represent amounts that the Bank plans to fund within a normal period of 60 to 90 days, many of which are intended for sale to investors in the secondary market. Total mortgage loans in the process of origination amounted to approximately $85.9 million and $69.3 million at December 31, 2020 and 2019, respectively. Letters of Credit Standby letters of credit are irrevocable conditional commitments issued by the Bank to guarantee the performance of a customer to a third party. Financial standby letters of credit are primarily issued to support public and private borrowing arrangements, including commercial paper, bond financing and similar transactions. Performance standby letters of credit are issued to guarantee performance of certain customers under nonfinancial contractual obligations. The credit risk involved in issuing standby letters of credit is essentially the same as that involved in extending loans to customers. Fees for letters of credit issued are initially recorded by the Bank as deferred revenue and are included in earnings at the termination of the respective agreements. Should the Bank be obligated to perform under the standby letters of credit, the Bank may seek recourse from the customer for reimbursement of amounts paid. The Company had total outstanding standby letters of credit amounting to approximately $16.1 million and $26.3 million at December 31, 2020 and 2019, respectively, with no letters of credit having terms over five years. Lines of Credit Lines of credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Lines of credit generally have fixed expiration dates. Since a portion of the line may expire without being drawn upon, the total unused lines do not necessarily represent future cash requirements. The Bank evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Bank upon extension of credit, is based on management’s credit evaluation of the counterparty. Collateral held varies but may include accounts receivable, inventory, property and equipment, commercial real estate and residential real estate. The Bank uses the same credit policies in granting lines of credit as it does for on-balance-sheet instruments. At December 31, 2020, the Bank had granted unused lines of credit to borrowers aggregating approximately $1.0 billion and $164.5 million for commercial lines and open-end consumer lines, respectively. At December 31, 2019, the Bank had granted unused lines of credit to borrowers aggregating approximately $1.2 billion and $155.8 million for commercial lines and open-end consumer lines, respectively. Credit Risk The Bank grants collateralized commercial, real estate and consumer loans primarily to customers in its market areas. Although the Bank has a diversified portfolio, loans (excluding those covered by loss sharing agreements) aggregating approximately $804.1 million and $725.0 million at December 31, 2020 and 2019, respectively, are secured primarily by apartments, condominiums, residential and commercial land developments, industrial revenue bonds and other types of commercial properties in the St. Louis, Missouri, area.

Additional Cash Flow Informatio

Additional Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Additional Cash Flow Information
Additional Cash Flow Information	Note 18: Additional Cash Flow Information ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) Noncash Investing and Financing Activities ​ ​ ​ ​ ​ ​ Real estate acquired in settlement of loans ​ $ 1,707 ​ $ 12,729 ​ $ 12,044 Sale and financing of foreclosed assets ​ 625 ​ 1,340 ​ 2,578 Conversion of premises and equipment to foreclosed assets ​ 80 ​ 1,135 ​ — Dividends declared but not paid ​ 4,676 ​ 4,849 ​ 4,528 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional Cash Payment Information ​ ​ ​ Interest paid ​ 42,221 ​ 53,922 ​ 37,091 Income taxes paid ​ 18,755 ​ 5,719 ​ 2,569 ​

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2020
Employee Benefits
Employee Benefits	Note 19: Employee Benefits The Company participates in the Pentegra Defined Benefit Plan for Financial Institutions (Pentegra DB Plan), a multiemployer defined benefit pension plan covering all employees who have met minimum service requirements. Effective July 1, 2006, this plan was closed to new participants. Employees already in the plan continue to accrue benefits. The Pentegra DB Plan’s Employer Identification Number is 13-5645888 and the Plan Number is 333. The Company’s policy is to fund pension cost accrued. Employer contributions charged to expense for this plan for the years ended December 31, 2020, 2019 and 2018, were approximately $2.1 million, $1.8 million and $1.3 million, respectively. The Company’s contributions to the Pentegra DB Plan were not more than 5 % of the total contributions to the plan. The funded status of the plan as of July 1, 2020 and 2019, was 92.5% and 93.7 %, respectively. The funded status was calculated by taking the market value of plan assets, which reflected contributions received through June 30, 2020 and 2019, respectively, divided by the funding target. No collective bargaining agreements are in place that require contributions to the Pentegra DB Plan. The Company has a defined contribution retirement plan covering substantially all employees. The Company matches 100% of the employee’s contribution on the first 3% of the employee’s compensation and also matches an additional 50% of the employee’s contribution on the next 2 % of the employee’s compensation. Employer contributions charged to expense for this plan for the years ended December 31, 2020, 2019 and 2018, were approximately $1.6 million, $1.4 million and $1.4 million, respectively.

Stock Compensation Plans

Stock Compensation Plans	12 Months Ended
	Dec. 31, 2020
Stock Compensation Plans
Stock Compensation Plans	Note 20: Stock Compensation Plans The Company established the 2003 Stock Option and Incentive Plan (the “2003 Plan”) for employees and directors of the Company and its subsidiaries. Under the plan, stock options or other awards could be granted with respect to 598,224 shares of common stock. On May 15, 2013, the Company’s stockholders approved the Great Southern Bancorp, Inc. 2013 Equity Incentive Plan (the “2013 Plan”). Upon the stockholders’ approval of the 2013 Plan, the Company’s 2003 Plan was frozen. As a result, no new stock options or other awards may be granted under the 2003 Plan; however, existing outstanding awards under the 2003 Plan were not affected. At December 31, 2020, 31,591 options were outstanding under the 2003 Plan. The Company established the 2013 Stock Option and Incentive Plan (the “2013 Plan”) for employees and directors of the Company and its subsidiaries. Under the plan, stock options or other awards could be granted with respect to 700,000 shares of common stock. On May 9, 2018, the Company’s stockholders approved the Great Southern Bancorp, Inc. 2018 Omnibus Incentive Plan (the “2018 Plan”). Upon the stockholders’ approval of the 2018 Plan, the Company’s 2013 Plan was frozen. As a result, no new stock options or other awards may be granted under the 2013 Plan; however, existing outstanding awards under the 2013 Plan were not affected. At December 31, 2020, 384,866 options were outstanding under the 2013 Plan. The 2018 Plan provides for the grant from time to time to directors, emeritus directors, officers, employees and advisory directors of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares and performance units. The number of shares of Common Stock available for awards under the 2018 Plan is 800,000 (the “2018 Plan Limit”). Shares utilized for awards other than stock options and stock appreciation rights will be counted against the 2018 Plan Limit on a 2.5 -to-1 basis. At December 31, 2020, 554,650 options were outstanding under the 2018 Plan. Stock options may be either incentive stock options or nonqualified stock options, and the option price must be at least equal to the fair value of the Company’s common stock on the date of grant. Options generally are granted for a 10 -year term and generally become exercisable in four cumulative annual installments of 25 % commencing two years from the date of grant. The Stock Option Committee may accelerate a participant’s right to purchase shares under the plan. Stock awards may be granted to key officers and employees upon terms and conditions determined solely at the discretion of the Stock Option Committee. The table below summarizes transactions under the Company’s stock compensation plans, all of which related to stock options granted under such plans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Weighted ​ ​ Available ​ Under ​ Average ​ ​ to Grant ​ Option ​ Exercise Price ​ ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2018 ​ 77,512 ​ 682,799 ​ $ 38.860 Granted from 2013 Plan (1,000) 1,000 ​ 52.500 Exercised — (81,940) ​ 27.597 Forfeited from 2013 Plan 13,773 (13,773) ​ 45.692 Termination of 2013 Plan (90,285) — ​ ​ ​ ​ — ​ 588,086 ​ ​ ​ Available to grant from 2018 Plan ​ 800,000 ​ — ​ ​ ​ Granted from 2018 Plan ​ (185,750) ​ 185,750 ​ ​ 55.297 Forfeited from current plan(s) ​ 600 ​ (600) ​ ​ 55.000 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 614,850 773,236 ​ 43.886 Granted from 2018 Plan (186,400) 186,400 ​ 60.086 Exercised — (125,894) ​ 33.031 Forfeited from terminated plan(s) — (17,424) ​ 44.163 Forfeited from current plan(s) 8,450 (8,450) ​ 55.000 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 436,900 807,868 ​ 49.139 Granted from 2018 Plan (196,350) 196,350 ​ 41.740 Exercised — (21,436) ​ 33.805 Forfeited from terminated plan(s) — (6,875) ​ 38.849 Forfeited from current plan(s) 4,800 (4,800) ​ 57.513 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 245,350 971,107 ​ $ 48.079 ​ The Company’s stock option grants contain terms that provide for a graded vesting schedule whereby portions of the options vest in increments over the requisite service period. These options typically vest one-fourth at the end of years two, three, four and five from the grant date. As provided for under FASB ASC 718, the Company has elected to recognize compensation expense for options with graded vesting schedules on a straight-line basis over the requisite service period for the entire option grant. In addition, ASC 718 requires companies to recognize compensation expense based on the estimated number of stock options for which service is expected to be rendered. The Company’s historical forfeitures of its share-based awards have not been material. The fair value of each option award is estimated on the date of the grant using the Black-Scholes option pricing model with the following assumptions for the years ended December 31, 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expected dividends per share ​ $ 1.36 ​ $ 1.36 ​ $ 1.27 Risk-free interest rate ​ 0.35 % ​ 1.59 % ​ 2.86 % Expected life of options ​ 5 years ​ ​ 5 years ​ ​ 5 years ​ Expected volatility ​ 29.32 % ​ 25.15 % ​ 17.61 % Weighted average fair value of options granted during year ​ $ 7.30 ​ $ 11.20 ​ $ 8.30 ​ ​ Expected volatilities are based on the historical volatility of the Company’s stock, based on the monthly closing stock price. The expected life of options granted is based on actual historical exercise behavior of all employees and directors and approximates the graded vesting period of the options. Expected dividends are based on the annualized dividends declared at the time of the option grant. The risk-free interest rate is based on the five-year treasury rate on the grant date of the options. The following table presents the activity related to options under all plans for the year ended December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ Average ​ Remaining ​ ​ ​ ​ Exercise ​ Contractual ​ Options Price Term ​ ​ ​ ​ ​ ​ ​ Options outstanding, January 1, 2020 807,868 ​ 49.139 7.54 years Granted 196,350 ​ 41.740 ​ Exercised (21,436) ​ 30.805 ​ Forfeited (11,675) ​ 46.523 ​ Options outstanding, December 31, 2020 971,107 ​ 48.079 7.23 years ​ ​ ​ ​ ​ ​ ​ Options exercisable, December 31, 2020 363,695 ​ 42.583 4.95 years ​ For the years ended December 31, 2020, 2019 and 2018, options granted were 196,350, 186,400, and 186,750 , respectively. The total intrinsic value (amount by which the fair value of the underlying stock exceeds the exercise price of an option on exercise date) of options exercised during the years ended December 31, 2020, 2019 and 2018, was $371,000, $3.1 million and $2.2 million, respectively. Cash received from the exercise of options for the years ended December 31, 2020, 2019 and 2018, was $661,000, $4.2 million and $2.2 million, respectively. The actual tax benefit realized for the tax deductions from option exercises totaled $257,000, $2.7 million and $1.6 million for the years ended December 31, 2020, 2019 and 2018, respectively. The total intrinsic value of options outstanding at December 31, 2020, 2019 and 2018, was $4.5 million, $11.5 million and $4.7 million, respectively. The total intrinsic value of options exercisable at December 31, 2020, 2019 and 2018, was $2.9 million, $6.6 million and $3.9 million, respectively. The following table presents the activity related to nonvested options under all plans for the year ended December 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ Exercise ​ Grant Date ​ Options Price Fair Value ​ ​ ​ ​ ​ ​ ​ Nonvested options, January 1, 2020 552,377 ​ 54.610 ​ 9.509 Granted 196,350 ​ 41.740 ​ 7.296 Vested this period (134,140) ​ 50.441 ​ 8.662 Nonvested options forfeited (7,175) ​ 54.655 ​ 9.501 ​ ​ ​ ​ ​ ​ ​ Nonvested options, December 31, 2020 607,412 ​ 51.370 ​ 8.981 ​ At December 31, 2020, there was $4.6 million of total unrecognized compensation cost related to nonvested options granted under the Company’s plans. This compensation cost is expected to be recognized through 2025, with the majority of this expense recognized in 2021 and 2022. The following table further summarizes information about stock options outstanding at December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Options Exercisable ​ ​ ​ ​ Average ​ Weighted ​ ​ ​ Weighted ​ ​ ​ ​ Remaining ​ Average ​ ​ ​ Average ​ ​ Number ​ Contractual ​ Exercise ​ Number ​ Exercise Range of Exercise Prices Outstanding Term Price Exercisable Price ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $16.810 to 29.640 64,043 2.16 years ​ $ 25.598 64,043 ​ $ 25.598 $32.590 to 38.610 62,056 3.62 years ​ 33.001 61,181 ​ 32.921 $41.300 to 47.800 282,357 8.56 years ​ 41.613 59,816 ​ 41.335 $50.710 to 52.500 204,251 6.11 years ​ 51.656 133,496 ​ 51.415 $55.000 to 60.150 358,400 8.35 years ​ 57.762 45,159 ​ 55.306 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 971,107 7.23 years ​ 48.079 363,695 ​ 42.583 ​

Significant Estimates and Conce

Significant Estimates and Concentrations	12 Months Ended
	Dec. 31, 2020
Significant Estimates and Concentration
Significant Estimates and Concentration	Note 21: Significant Estimates and Concentrations Accounting principles generally accepted in the United States of America require disclosure of certain significant estimates and current vulnerabilities due to certain concentrations. Estimates related to the allowance for loan losses are reflected in Note 3 Other significant estimates not discussed in those footnotes include valuations of foreclosed assets held for sale. The carrying value of foreclosed assets reflects management’s best estimate of the amount to be realized from the sales of the assets. While the estimate is generally based on a valuation by an independent appraiser or recent sales of similar properties, the amount that the Company realizes from the sales of the assets could differ materially in the near term from the carrying value reflected in these financial statements.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income	Note 22: Accumulated Other Comprehensive Income The components of accumulated other comprehensive income (AOCI), included in stockholders’ equity, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Net unrealized gain on available-for-sale securities ​ $ 30,126 ​ $ 11,715 ​ ​ ​ ​ ​ ​ ​ Net unrealized gain on derivatives used for cash flow hedges ​ 38,724 ​ 30,056 ​ ​ 68,850 ​ 41,771 ​ ​ ​ ​ ​ ​ ​ Tax effect ​ (15,699) ​ (9,525) ​ ​ ​ ​ ​ ​ ​ Net-of-tax amount ​ $ 53,151 ​ $ 32,246 ​ Amounts reclassified from AOCI and the affected line items in the statements of income during the years ended December 31, 2020, 2019 and 2018, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts Reclassified ​ ​ ​ from AOCI ​ Affected Line Item in the ​ 2020 2019 2018 Statements of Income ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized gains/(losses) on available- for-sale securities ​ $ 78 ​ $ (62) ​ $ 2 Net realized gains on available-for-sale securities (total reclassified amount before tax) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in fair value of cash flow hedge ​ ​ 6,764 ​ ​ — ​ ​ — ​ Amortization of realized gain on termination of cash flow hedge (total reclassification amount before tax) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income taxes ​ (1,559) ​ 14 ​ — Tax (expense) benefit ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications out of AOCI ​ $ 5,283 ​ $ 48 ​ $ 2 ​

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2020
Regulatory Matters
Regulatory Matters	Note 23: Regulatory Matters The Company and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can result in certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct and material effect on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of the Company’s and the Bank’s assets, liabilities and certain off-balance-sheet items as calculated under U.S. GAAP, regulatory reporting practices, and regulatory capital standards. The Company’s and the Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. Quantitative measures established by regulatory reporting standards to ensure capital adequacy require the Bank to maintain minimum amounts and ratios (set forth in the table below as of December 31, 2020) of Total and Tier I Capital (as defined) to risk-weighted assets (as defined), of Tier I Capital (as defined) to adjusted tangible assets (as defined) and of Common Equity Tier 1 Capital (as defined) to risk-weighted assets (as defined). Management believes, as of December 31, 2020, that the Bank met all capital adequacy requirements to which it was then subject. As of December 31, 2020, the most recent notification from the Bank’s regulators categorized the Bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well capitalized as of December 31, 2020, the Bank must have maintained minimum Total capital, Tier I capital, Tier 1 Leverage capital and Common Equity Tier 1 capital ratios as set forth in the table. There are no conditions or events since that notification that management believes have changed the Bank’s category. The Company and the Bank are subject to certain restrictions on the amount of dividends that may be declared without prior regulatory approval. At December 31, 2020 and 2019, the Company and the Bank exceeded their minimum capital requirements then in effect. The entities may not pay dividends which would reduce capital below the minimum requirements shown above. In addition to the minimum capital ratios, the capital rules include a capital conservation buffer, under which a banking organization must have Common Equity Tier 1 capital more than 2.5% above each of its minimum risk-based capital ratios in order to avoid restrictions on paying dividends, repurchasing shares, and paying certain discretionary bonuses. The net unrealized gain or loss on available-for-sale securities is not included in computing regulatory capital. The Company’s and the Bank’s actual capital amounts and ratios are presented in the following table. No amount was deducted from capital for interest-rate risk. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ To Be Well ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Capitalized Under ​ ​ ​ ​ ​ ​ ​ For Capital ​ Prompt Corrective ​ ​ Actual ​ Adequacy Purposes ​ Action Provisions ​ Amount Ratio Amount Ratio Amount Ratio ​ ​ (Dollars In Thousands) As of December 31, 2020 ​ ​ ​ ​ Total capital ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 800,388 17.2 % $ 373,132 8.0 % ​ N/A N/A ​ Great Southern Bank ​ $ 694,047 14.9 % $ 373,058 8.0 % $ 466,322 10.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 594,645 12.7 % $ 279,849 6.0 % N/A N/A ​ Great Southern Bank ​ $ 638,304 13.7 % $ 279,793 6.0 % $ 373,058 8.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I leverage capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 594,645 10.9 % $ 217,223 4.0 % N/A N/A ​ Great Southern Bank ​ $ 638,304 11.8 % $ 217,170 4.0 % $ 271,463 5.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common equity Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 569,645 12.2 % $ 209,887 4.5 % N/A N/A ​ Great Southern Bank ​ $ 638,304 13.7 % $ 209,845 4.5 % $ 303,109 6.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Total capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 698,085 15.0 % $ 372,387 8.0 % N/A N/A ​ Great Southern Bank ​ $ 650,280 14.0 % $ 372,316 8.0 % $ 465,395 10.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 582,791 12.5 % $ 279,290 6.0 % N/A N/A ​ Great Southern Bank ​ $ 609,986 13.1 % $ 279,237 6.0 % $ 372,316 8.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I leverage capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 582,791 11.8 % $ 198,320 4.0 % N/A N/A ​ Great Southern Bank ​ $ 609,986 12.3 % $ 198,010 4.0 % $ 247,512 5.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common equity Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 557,791 12.0 % $ 209,468 4.5 % N/A N/A ​ Great Southern Bank ​ $ 609,986 13.1 % $ 209,428 4.5 % $ 302,507 6.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Litigation Matters

Litigation Matters	12 Months Ended
	Dec. 31, 2020
Litigation Matters
Litigation Matters	Note 24: Litigation Matters In the normal course of business, the Company and its subsidiaries are subject to pending and threatened legal actions, some of which seek substantial relief or damages. While the ultimate outcome of such legal proceedings cannot be predicted with certainty, after reviewing pending and threatened litigation with counsel, management believes at this time that the outcome of such litigation will not have a material adverse effect on the Company’s business, financial condition or results of operations.

Summary of Unaudited Quarterly

Summary of Unaudited Quarterly Operating Results	12 Months Ended
	Dec. 31, 2020
Summary of Unaudited Quarterly Operating Results
Summary of Unaudited Quarterly Operating Results	Note 25: Summary of Unaudited Quarterly Operating Results Following is a summary of unaudited quarterly operating results for the years 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 57,474 ​ $ 54,011 ​ $ 53,599 ​ $ 52,619 Interest expense ​ 12,536 ​ 10,556 ​ 9,431 ​ 8,042 Provision for loan losses ​ 3,871 ​ 6,000 ​ 4,500 ​ 1,500 Net realized gains on available-for-sale securities ​ — ​ 78 ​ — ​ — Noninterest income ​ 7,367 ​ 8,261 ​ 9,466 ​ 9,956 Noninterest expense ​ 30,815 ​ 29,349 ​ 31,988 ​ 31,073 Provision for income taxes ​ 2,751 ​ 3,164 ​ 3,692 ​ 4,172 Net income available to common shareholders ​ 14,868 ​ 13,203 ​ 13,454 ​ 17,788 Earnings per common share – diluted ​ 1.04 ​ 0.93 ​ 0.96 ​ 1.28 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 57,358 ​ $ 58,723 ​ $ 60,187 ​ $ 58,726 Interest expense ​ 12,753 ​ 13,802 ​ 14,263 ​ 13,784 Provision for loan losses ​ 1,950 ​ 1,600 ​ 1,950 ​ 650 Net realized gains (losses) on available-for-sale securities ​ 10 ​ — ​ — ​ (72) Noninterest income ​ 7,450 ​ 7,157 ​ 8,655 ​ 7,695 Noninterest expense ​ 28,495 ​ 28,383 ​ 28,725 ​ 29,535 Provision for income taxes ​ 3,998 ​ 3,720 ​ 4,172 ​ 4,559 Net income available to common shareholders ​ 17,612 ​ 18,375 ​ 19,732 ​ 17,893 Earnings per common share – diluted ​ 1.23 ​ 1.28 ​ 1.38 ​ 1.24 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 46,882 ​ $ 49,943 ​ $ 52,982 ​ $ 56,142 Interest expense ​ 7,444 ​ 8,731 ​ 9,997 ​ 11,585 Provision for loan losses ​ 1,950 ​ 1,950 ​ 1,300 ​ 1,950 Net realized gains on available-for-sale securities ​ — ​ — ​ 2 ​ — Noninterest income ​ 6,935 ​ 7,459 ​ 14,604 ​ 7,220 Noninterest expense ​ 28,312 ​ 29,915 ​ 28,309 ​ 28,774 Provision for income taxes ​ 2,645 ​ 2,967 ​ 5,464 ​ 3,765 Net income available to common shareholders ​ 13,466 ​ 13,839 ​ 22,516 ​ 17,288 Earnings per common share – diluted ​ 0.95 ​ 0.97 ​ 1.57 ​ 1.21 ​

Condensed Parent Company Statem

Condensed Parent Company Statements	12 Months Ended
	Dec. 31, 2020
Condensed Parent Company Statements
Condensed Parent Company Statements	Note 26: Condensed Parent Company Statements The condensed statements of financial condition at December 31, 2020 and 2019, and statements of income, comprehensive income and cash flows for the years ended December 31, 2020, 2019 and 2018, for the parent company, Great Southern Bancorp, Inc., were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (In Thousands) Statements of Financial Condition ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets ​ ​ ​ ​ ​ ​ Cash ​ $ 111,250 ​ $ 58,726 Investment in subsidiary bank ​ 698,398 ​ 650,329 Deferred and accrued income taxes ​ 157 ​ 111 Prepaid expenses and other assets ​ 883 ​ 868 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 810,688 ​ $ 710,034 ​ ​ ​ ​ ​ ​ ​ Liabilities and Stockholders’ Equity ​ ​ ​ ​ Accounts payable and accrued expenses ​ $ 6,776 ​ $ 6,918 Subordinated debentures issued to capital trust ​ 25,774 ​ 25,774 Subordinated notes ​ 148,397 ​ 74,276 Common stock ​ 138 ​ 143 Additional paid-in capital ​ 35,004 ​ 33,510 Retained earnings ​ 541,448 ​ 537,167 Accumulated other comprehensive income ​ 53,151 ​ 32,246 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 810,688 ​ $ 710,034 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income ​ ​ ​ Dividends from subsidiary bank ​ $ 40,000 ​ $ 32,000 ​ $ 34,000 Other income ​ 5 ​ — ​ — Loss on other investments ​ — ​ (23) ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 40,005 ​ 31,977 ​ 34,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expense ​ ​ ​ ​ ​ ​ Operating expenses ​ 2,197 ​ 2,044 ​ 1,793 Interest expense ​ 7,459 ​ 5,397 ​ 5,050 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9,656 ​ 7,441 ​ 6,843 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income tax and equity in undistributed earnings of subsidiaries ​ 30,349 ​ 24,536 ​ 27,157 Credit for income taxes ​ (1,800) ​ (1,381) ​ (1,204) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before equity in earnings of subsidiaries ​ 32,149 ​ 25,917 ​ 28,361 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity in undistributed earnings of subsidiaries ​ 27,164 ​ 47,695 ​ 38,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Cash Flows ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Activities ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 Items not requiring (providing) cash ​ ​ ​ ​ ​ ​ Equity in undistributed earnings of subsidiary ​ (27,164) ​ (47,695) ​ (38,748) Compensation expense for stock option grants ​ 1,153 ​ 922 ​ 737 Amortization of interest rate derivative and deferred costs on subordinated notes ​ 608 ​ 434 ​ 154 Loss on other investments ​ — ​ 23 ​ — Changes in ​ ​ ​ ​ ​ ​ Prepaid expenses and other assets ​ (15) ​ (3) ​ 13 Accounts payable and accrued expenses ​ 31 ​ 226 ​ 182 Income taxes ​ (46) ​ 300 ​ (278) Net cash provided by operating activities ​ 33,880 ​ 27,819 ​ 29,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investing Activities ​ ​ ​ Return of principal - other investments ​ — ​ 2 ​ — Net cash provided by investing activities ​ — ​ 2 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financing Activities ​ ​ ​ Purchases of the Company’s common stock ​ (22,104) ​ (849) ​ (903) Proceeds from issuance of subordinated notes ​ ​ 73,513 ​ ​ — ​ ​ — Dividends paid ​ (33,426) ​ (29,052) ​ (15,819) Stock options exercised ​ 661 ​ 4,158 ​ 2,224 Net cash used in financing activities ​ 18,644 ​ (25,743) ​ (14,498) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Increase in Cash ​ 52,524 ​ 2,078 ​ 14,671 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash, Beginning of Year ​ 58,726 ​ 56,648 ​ 41,977 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash, End of Year ​ $ 111,250 ​ $ 58,726 ​ $ 56,648 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional Cash Payment Information ​ ​ ​ ​ ​ ​ Interest paid ​ $ 7,349 ​ $ 5,424 ​ $ 5,001 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Comprehensive Income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income of subsidiaries ​ 20,905 ​ 22,619 ​ 8,114 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive Income ​ $ 80,218 ​ $ 96,231 ​ $ 75,223 ​

Sale of Branches and Related De

Sale of Branches and Related Deposits	12 Months Ended
	Dec. 31, 2020
Sale of Branches and Related Deposits
Sale of Branches and Related Deposits	Note 27: Sale of Branches and Related Deposits On July 20, 2018, the Company closed on the sale of four banking centers and related deposits in the Omaha, Neb., metropolitan market to Lincoln, Neb.-based West Gate Bank. Pursuant to the purchase and assumption agreement, the Bank sold branch deposits of approximately $56 million and substantially all branch-related real estate, fixed assets and ATMs. The Company recorded a pre-tax gain (excluding transaction expenses of $165,000) of $7.4 million on the sale based on the contractual deposit premium and the sales price of the branch assets.

Nature of Operations and Summ_2

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Summary of Significant Accounting Policies
Nature of Operations and Operating Segments	Nature of Operations and Operating Segments Great Southern Bancorp, Inc. (“GSBC” or the “Company”) operates as a one-bank holding company. GSBC’s business primarily consists of the operations of Great Southern Bank (the “Bank”), which provides a full range of financial services to customers primarily located in Missouri, Iowa, Kansas, Minnesota, Nebraska and Arkansas. The Bank also originates commercial loans from lending offices in Atlanta, Ga., Chicago, Ill., Dallas, Texas, Denver, Colo., Omaha, Neb. and Tulsa, Okla. The Company and the Bank are subject to regulation by certain federal and state agencies and undergo periodic examinations by those regulatory agencies. The Company’s banking operation is its only reportable segment. The banking operation is principally engaged in the business of originating residential and commercial real estate loans, construction loans, commercial business loans and consumer loans and funding these loans by attracting deposits from the general public, accepting brokered deposits and borrowing from the Federal Home Loan Bank and others. The operating results of this segment are regularly reviewed by management to make decisions about resource allocations and to assess performance. Selected information is not presented separately for the Company’s reportable segment, as there is no material difference between that information and the corresponding information in the consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses and the valuation of real estate acquired in connection with foreclosures or in satisfaction of loans, the valuation of loans acquired with indication of impairment and other-than-temporary impairments (OTTI) and fair values of financial instruments. In connection with the determination of the allowance for loan losses and the valuation of foreclosed assets held for sale, management obtains independent appraisals for significant properties. In addition, the Company considers that the determination of the carrying value of goodwill and intangible assets involves a high degree of judgment and complexity.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Great Southern Bancorp, Inc., its wholly owned subsidiary, the Bank, and the Bank’s wholly owned subsidiaries, Great Southern Real Estate Development Corporation, GSB One LLC (including its wholly owned subsidiary, GSB Two LLC), Great Southern Financial Corporation, Great Southern Community Development Company, LLC (including its wholly owned subsidiary, Great Southern CDE, LLC), GS, LLC, GSSC, LLC, GSTC Investments, LLC, GS-RE Holding, LLC (including its wholly owned subsidiary, GS RE Management, LLC), GS-RE Holding II, LLC, GS-RE Holding III, LLC, VFP Conclusion Holding, LLC and VFP Conclusion Holding II, LLC. All significant intercompany accounts and transactions have been eliminated in consolidation.
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock Federal Home Loan Bank common stock is a required investment for institutions that are members of the Federal Home Loan Bank system. The required investment in common stock is based on a predetermined formula, carried at cost and evaluated for impairment.
Securities	Securities Available-for-sale securities, which include any security for which the Company has no immediate plan to sell but which may be sold in the future, are carried at fair value. Unrealized gains and losses are recorded, net of related income tax effects, in other comprehensive income. Held-to-maturity securities, which include any security for which the Company has the positive intent and ability to hold until maturity, are carried at historical cost adjusted for amortization of premiums and accretion of discounts. Amortization of premiums and accretion of discounts are recorded as interest income from securities. Realized gains and losses are recorded as net security gains (losses). Gains and losses on sales of securities are determined on the specific-identification method. For debt securities with fair value below carrying value when the Company does not intend to sell a debt security, and it is more likely than not the Company will not have to sell the security before recovery of its cost basis, it recognizes the credit component of an other-than-temporary impairment (“OTTI”) of a debt security in earnings and the remaining portion in other comprehensive income. For held-to-maturity debt securities, the amount of an OTTI recorded in other comprehensive income for the noncredit portion of a previous OTTI is amortized prospectively over the remaining life of the security on the basis of the timing of future estimated cash flows of the security. The Company’s consolidated statements of income reflect the full impairment (that is, the difference between the security’s amortized cost basis and fair value) on debt securities that the Company intends to sell or would more likely than not be required to sell before the expected recovery of the amortized cost basis. For available-for-sale and held-to-maturity debt securities that management has no intent to sell and believes that it more likely than not will not be required to sell prior to recovery, only the credit loss component of the impairment is recognized in earnings, while the noncredit loss is recognized in accumulated other comprehensive income. The credit loss component recognized in earnings is identified as the amount of principal cash flows not expected to be received over the remaining term of the security based on cash flow projections. For equity securities, if any, when the Company has decided to sell an impaired available-for-sale security and the Company does not expect the fair value of the security to fully recover before the expected time of sale, the security is deemed OTTI in the period in which the decision to sell is made. The Company recognizes an impairment loss when the impairment is deemed other-than-temporary even if a decision to sell has not been made.
Mortgage Loans Held for Sale	Mortgage Loans Held for Sale Mortgage loans originated and intended for sale in the secondary market are carried at the lower of cost or fair value in the aggregate. Write-downs to fair value are recognized as a charge to earnings at the time the decline in value occurs. Nonbinding forward commitments to sell individual mortgage loans are generally obtained to reduce market risk on mortgage loans in the process of origination and mortgage loans held for sale. Gains and losses resulting from sales of mortgage loans are recognized when the respective loans are sold to investors. Fees received from borrowers to guarantee the funding of mortgage loans held for sale and fees paid to investors to ensure the ultimate sale of such mortgage loans are recognized as income or expense when the loans are sold or when it becomes evident that the commitment will not be used.
Loans Originated by the Company	Loans Originated by the Company Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at their outstanding principal balances adjusted for any charge-offs, the allowance for loan losses, any deferred fees or costs on originated loans and unamortized premiums or discounts on purchased loans. Interest income is reported on the interest method and includes amortization of net deferred loan fees and costs over the loan term. Past due status is based on the contractual terms of a loan. Generally, loans are placed on nonaccrual status at 90 days past due and interest is considered a loss, unless the loan is well secured and in the process of collection. Payments received on nonaccrual loans are applied to principal until the loans are returned to accrual status. Loans are returned to accrual status when all payments contractually due are brought current, payment performance is sustained for a period of time, generally six months, and future payments are reasonably assured. With the exception of consumer loans, charge-offs on loans are recorded when available information indicates a loan is not fully collectible and the loss is reasonably quantifiable. Consumer loans are charged-off at specified delinquency dates consistent with regulatory guidelines.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is established as losses are estimated to have occurred through a provision for loan losses charged to earnings. Loan losses are charged against the allowance when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance consists of allocated and general components. The allocated component relates to loans that are classified as impaired. For loans classified as impaired, an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The general component covers non-classified loans and is based on historical charge-off experience and expected loss given default derived from the Company’s internal risk rating process. Other adjustments may be made to the allowance for certain loan segments after an assessment of internal or external influences on credit quality that are not fully reflected in the historical loss or risk rating data. A loan is considered impaired when, based on current information and events, it is probable that not all of the principal and interest due under the loan agreement will be collected in accordance with contractual terms. For non-homogeneous loans, such as commercial loans, management determines which loans are reviewed for impairment based on information obtained by account officers, weekly past due meetings, various analyses including annual reviews of large loan relationships, calculations of loan debt coverage ratios as financial information is obtained and periodic reviews of all loans over $1.0 million. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length and reasons for the delay, the borrower’s prior payment record and the amount of any collateral shortfall in relation to the principal and interest owed. Large groups of smaller balance homogenous loans, such as consumer and residential loans, are collectively evaluated for impairment. In accordance with regulatory guidelines, impairment in the consumer and mortgage loan portfolio is primarily identified based on past-due status. Consumer and mortgage loans which are over 90 days past due or specifically identified as troubled debt restructurings will generally be individually evaluated for impairment. Impairment is measured on a loan-by-loan basis for both homogeneous and non-homogeneous loans by either the present value of expected future cash flows or the fair value of the collateral if the loan is collateral dependent. Payments made on impaired loans are treated in accordance with the accrual status of the loan. If loans are performing in accordance with their contractual terms but the ultimate collectability of principal and interest is questionable, payments are applied to principal only.
Loans Acquired in Business Combination	Loans Acquired in Business Combinations Loans acquired in business combinations under ASC Topic 805, Business Combinations Fair Value Measurements and Disclosures For acquired loans not acquired in conjunction with an FDIC-assisted transaction that are not considered to be purchased credit-impaired loans, the Company evaluates those loans acquired in accordance with the provisions of ASC Topic 310-20, Nonrefundable Fees and Other Costs Loans and Debt Securities Acquired with Deteriorated Credit Quality The Company evaluates all of its loans acquired in conjunction with its FDIC-assisted transactions in accordance with the provisions of ASC Topic 310-30. For purposes of applying ASC 310-30, loans acquired in FDIC-assisted business combinations are aggregated into pools of loans with common risk characteristics. All loans acquired in the FDIC transactions, both covered and not covered by loss sharing agreements, were deemed to be purchased credit-impaired loans as there is general evidence of credit deterioration since origination in the pools and there is some probability that not all contractually required payments will be collected. As a result, related discounts are recognized subsequently through accretion based on changes in the expected cash flows of these acquired loans. The expected cash flows of the acquired loan pools in excess of the fair values recorded is referred to as the accretable yield and is recognized in interest income over the remaining estimated lives of the loan pools for impaired loans accounted for under ASC Topic 310-30. Subsequent to acquisition date, the Company has estimated cash flows expected to be collected on pools of loans sharing common risk characteristics, which are treated in the aggregate when applying various valuation techniques. Increases in the Company’s cash flow expectations have been recognized as increases to the accretable yield while decreases have been recognized as impairments through the allowance for loan losses.
Other Real Estate Owned and Repossessions	Other Real Estate Owned and Repossessions Assets acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value less estimated cost to sell at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, valuations are periodically performed by management and the assets are carried at the lower of carrying amount or fair value less estimated cost to sell. Revenue and expenses from operations and changes in the valuation allowance are included in net expense on foreclosed assets. Other real estate owned also includes bank premises formerly, but no longer, used for banking, as well as property originally acquired for future expansion but no longer intended to be used for that purpose.
Premises and Equipment	Premises and Equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation is charged to expense using the straight-line and accelerated methods over the estimated useful lives of the assets. Leasehold improvements are capitalized and amortized using the straight-line and accelerated methods over the terms of the respective leases or the estimated useful lives of the improvements, whichever is shorter. Material lease obligations consist of leases for various loan offices and banking centers, all of which are categorized as “operating leases.” Under current accounting guidance, lessees are required to recognize a lease liability and a right-of-use asset for these leases. This right-of-use asset is included in Premises and Equipment.
Long-Lived Asset Impairment	Long-Lived Asset Impairment The Company evaluates the recoverability of the carrying value of long-lived assets whenever events or circumstances indicate the carrying amount may not be recoverable. If a long-lived asset is tested for recoverability and the undiscounted estimated future cash flows expected to result from the use and eventual disposition of the asset is less than the carrying amount of the asset, the asset cost is adjusted to fair value and an impairment loss is recognized as the amount by which the carrying amount of a long-lived asset exceeds its fair value. No asset impairment was recognized during the years ended December 31, 2020, 2019 and 2018.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill is evaluated annually for impairment or more frequently if impairment indicators are present. The annual, or interim, goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount and an impairment charge is recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. The Company still may perform the qualitative assessment for a reporting unit to determine if the qualitative impairment test is necessary. Intangible assets are being amortized on the straight-line basis generally over a period of seven years . Such assets are periodically evaluated as to the recoverability of their carrying value. A summary of goodwill and intangible assets is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Goodwill – Branch acquisitions ​ $ 5,396 ​ $ 5,396 Deposit intangibles ​ ​ Boulevard Bank ​ 31 ​ 153 Valley Bank ​ 200 ​ 600 Fifth Third Bank ​ 1,317 ​ 1,949 ​ ​ 1,548 ​ 2,702 ​ ​ $ 6,944 ​ $ 8,098 ​
Loan Servicing and Origination Fee Income	Loan Servicing and Origination Fee Income Loan servicing income represents fees earned for servicing real estate mortgage loans owned by various investors. The fees are generally calculated on the outstanding principal balances of the loans serviced and are recorded as income when earned. Loan origination fees, net of direct loan origination costs, are recognized as income using the level-yield method over the contractual life of the loan.
Stockholders' Equity	Stockholders’ Equity The Company is incorporated in the State of Maryland. Under Maryland law, there is no concept of “Treasury Shares.” Instead, shares purchased by the Company constitute authorized but unissued shares under Maryland law. Accounting principles generally accepted in the United States of America state that accounting for treasury stock shall conform to state law. The cost of shares purchased by the Company has been allocated to common stock and retained earnings balances.
Earnings Per Common Share	Earnings Per Common Share Basic earnings per common share are computed based on the weighted average number of common shares outstanding during each year. Diluted earnings per common share are computed using the weighted average common shares and all potential dilutive common shares outstanding during the period. Earnings per common share (EPS) were computed as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income and net income available to common shareholders ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common shares outstanding ​ 14,043 ​ 14,201 ​ 14,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common share stock options outstanding ​ 61 ​ 129 ​ 128 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average diluted common shares ​ 14,104 ​ 14,330 ​ 14,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – basic ​ $ 4.22 ​ $ 5.18 ​ $ 4.75 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – diluted ​ $ 4.21 ​ $ 5.14 ​ $ 4.71 ​ Options outstanding at December 31, 2020, 2019 and 2018, to purchase 758,901, 201,400 and 424,833 shares of common stock, respectively, were not included in the computation of diluted earnings per common share for each of the years because the exercise prices of such options were greater than the average market prices of the common stock for the years ended December 31, 2020, 2019 and 2018, respectively.
Stock Compensation Plans	Stock Compensation Plans The Company has stock-based employee compensation plans, which are described more fully in Note 20 . In accordance with FASB ASC 718, Compensation – Stock Compensation , compensation cost related to share-based payment transactions is recognized in the Company’s consolidated financial statements based on the grant-date fair value of the award using the modified prospective transition method. For the years ended December 31, 2020, 2019 and 2018, share-based compensation expense totaling $1.2 million, $922,000 and $737,000, respectively, was included in salaries and employee benefits expense in the consolidated statements of income.
Cash Equivalents	Cash Equivalents The Company considers all liquid investments with original maturities of three months or less to be cash equivalents. At December 31, 2020 and 2019, cash equivalents consisted of interest-bearing deposits in other financial institutions. At December 31, 2020, nearly all of the interest-bearing deposits were uninsured with nearly all of these balances held at the Federal Home Loan Bank or the Federal Reserve Bank.
Income Taxes	Income Taxes The Company accounts for income taxes in accordance with income tax accounting guidance (FASB ASC 740, Income Taxes Deferred income tax expense results from changes in deferred tax assets and liabilities between periods. Deferred tax assets are recognized if it is more likely than not, based on the technical merits, that the tax position will be realized or sustained upon examination. The term “more likely than not” means a likelihood of more than 50 percent; the terms examined and upon examination also include resolution of the related appeals or litigation processes, if any. A tax position that meets the more-likely-than-not recognition threshold is initially and subsequently measured as the largest amount of tax benefit that has a greater than 50 percent likelihood of being realized upon settlement with a taxing authority that has full knowledge of all relevant information. The determination of whether or not a tax position has met the more-likely-than-not recognition threshold considers the facts, circumstances and information available at the reporting date and is subject to management’s judgment. Deferred tax assets are reduced by a valuation allowance if, based on the weight of evidence available, it is more likely than not that some portion or all of a deferred tax asset will not be realized. At December 31, 2020 and 2019, no valuation allowance was established. The Company recognizes interest and penalties on income taxes as a component of income tax expense. The Company files consolidated income tax returns with its subsidiaries.
Derivatives and Hedging Activities	Derivatives and Hedging Activities FASB ASC 815, Derivatives and Hedging Note 16 As required by FASB ASC 815, the Company records all derivatives in the statement of financial condition at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting.
Restrictions on Cash and Due From Banks	Restriction on Cash and Due From Banks The Bank is required to maintain reserve funds in cash and/or on deposit with the Federal Reserve Bank. During the COVID-19 pandemic, the Federal Reserve Bank has reduced all banks’ reserve requirements to $-0- until further notice. There was no reserve required at December 31, 2020, compared to $69.4 million at December 31, 2019.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326) . The Update amends guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, Topic 326 eliminates the probable initial recognition threshold in current GAAP and, instead, requires an entity to reflect its current estimate of all expected credit losses. This Update affects entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The amendments affect loans, debt securities, trade receivables, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. The Update was set to be effective for the Company on January 1, 2020. During March 2020, pursuant to the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) and guidance from the Securities and Exchange Commission (the “SEC”) and the Financial Accounting Standards Board (the “FASB”), we elected to delay adoption of the new accounting standard related to accounting for credit losses (“CECL”). In December 2020, additional legislation was enacted that amended certain provisions of the CARES Act. One of the provisions that was affected by this new legislation allowed for the election to further delay the adoption of the CECL accounting standard to January 1, 2022. An adoption date of January 1, 2021, was also an acceptable option and we elected January 1, 2021 as our adoption date for the CECL standard. As a result, our 2020 financial statements are prepared under the existing incurred loss methodology standard for accounting for loan losses. The adoption of the CECL model during the first quarter of 2021 requires us to recognize a one-time cumulative adjustment to our allowance for loan losses and a liability for potential losses related to the unfunded portion of our loans and commitments in order to fully transition from the incurred loss model to the CECL model. Upon initial adoption, we increased the balance of our allowance for credit losses by approximately $12 million and create a liability for potential losses related to the unfunded portion of our loans and commitments by approximately $8 million. The after-tax effect of these adjustments is expected to result in a decrease in our retained earnings of approximately $13 million. These estimates are subject to change as material assumptions are refined and model validations are completed as we finalize our first quarter 2021 financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles: Goodwill and Other: Simplifying the Test for Goodwill Impairment (Topic 350) . To simplify the subsequent measurement of goodwill, the amendments eliminate Step 2 from the goodwill impairment test. The annual, or interim, goodwill impairment test should be performed by comparing the fair value of a reporting unit with its carrying amount and an impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the qualitative impairment test is necessary. The nature of and reason for the change in accounting principle should be disclosed upon transition. The amendments in this update are required for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. The impact of adopting this new guidance during the quarter ended March 31, 2020 did not have a material impact on the Company’s consolidated financial statements. During 2020, the Company performed its annual review of goodwill and intangibles, including consideration of the circumstances brought about by the COVID-19 pandemic and its effect on the valuation of the Company and other bank holding companies. The Company concluded that no impairment of its goodwill and intangible assets had occurred in 2020. In August 2018, the FASB issued ASU 2018-13 , Fair Value Measurement (Topic 820) - Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement . ASU 2018-13 modifies the disclosure requirements on fair value measurements in Topic 820. The amendments in this update remove disclosures that no longer are considered cost beneficial, modify/clarify the specific requirements of certain disclosures, and add disclosure requirements identified as relevant. ASU 2018-13 is effective for periods beginning after December 15, 2019. The impact of adopting this new guidance during the quarter ended March 31, 2020 did not have a material impact on the Company’s consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope.
Investments in Affordable Housing Partnerships	Investments in Affordable Housing Partnerships The Company has invested in certain limited partnerships that were formed to develop and operate apartments and single-family houses designed as high-quality affordable housing for lower income tenants throughout Missouri and contiguous states. At December 31, 2020 the Company had 16 such investments, with a net carrying value of $20.4 million. At December 31, 2019 the Company had 15 such investments, with a net carrying value of $22.8 million. Due to the Company’s inability to exercise any significant influence over any of the investments in Affordable Housing Partnerships, they all are accounted for using the proportional amortization method. Each of the partnerships must meet the regulatory requirements for affordable housing for a minimum 15-year compliance period to fully utilize the tax credits. If the partnerships cease to qualify during the compliance period, the credits may be denied for any period in which the projects are not in compliance and a portion of the credits previously taken may be subject to recapture with interest. The remaining federal affordable housing tax credits to be utilized through 2030 were $22.1 million as of December 31, 2020, assuming no tax credit recapture events occur and all projects currently under construction are completed as planned. Amortization of the investments in partnerships is expected to be approximately $20.4 million, assuming all projects currently under construction are completed and funded as planned. The Company’s usage of federal affordable housing tax credits approximated $6.6 million, $8.0 million and $6.6 million during 2020, 2019 and 2018, respectively. Investment amortization amounted to $5.5 million, $5.8 million and $5.0 million for the years ended December 31, 2020, 2019 and 2018, respectively.
Investments in Community Development Entities	Investments in Community Development Entities The Company has invested in certain limited partnerships that were formed to develop and operate business and real estate projects located in low-income communities. At December 31, 2020 the Company had one such investment, with a net carrying value of $567,000 . At December 31, 2019, the Company had no such investment. Due to the Company’s inability to exercise any significant influence over any of the investments in qualified Community Development Entities, they are all accounted for using the cost method. Each of the partnerships provides federal New Market Tax Credits over a seven-year credit allowance period. In each of the first three years, credits totaling five percent of the original investment are allowed on the credit allowance dates and for the final four years, credits totaling six percent of the original investment are allowed on the credit allowance dates. Each of the partnerships must be invested in a qualified Community Development Entity on each of the credit allowance dates during the seven-year period to utilize the tax credits. If the Community Development Entities cease to qualify during the seven-year period, the credits may be denied for any credit allowance date and a portion of the credits previously taken may be subject to recapture with interest. The investments in the Community Development Entities cannot be redeemed before the end of the seven-year period. The Company’s usage of federal New Market Tax Credits approximated $100,000, $480,000 and $480,000 during 2020, 2019 and 2018, respectively. Investment amortization amounted to $80,000, $365,000 and $575,000 for the years ended December 31, 2020, 2019 and 2018, respectively.
Investments in Limited Partnerships for Federal Rehabilitation/Historic Tax Credits	Investments in Limited Partnerships for Federal Rehabilitation/Historic Tax Credits From time to time, the Company has invested in certain limited partnerships that were formed to provide certain federal rehabilitation/historic tax credits. At December 31, 2020 the Company had one such investments, with a net carrying value of $863,000. Previously, the Company utilized these credits in their entirety in the year the project was placed in service and the impact to the Consolidated Statements of Income has not been material. In future periods, such partnerships provide federal rehabilitation/historic tax credits over a five-year credit allowance period.
Investments in Limited Partnerships for State Tax Credits	Investments in Limited Partnerships for State Tax Credits From time to time, the Company has invested in certain limited partnerships that were formed to provide certain state tax credits. The Company has primarily syndicated these tax credits and the impact to the Consolidated Statements of Income has not been material.

Nature of Operations and Summ_3

Nature of Operations and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Summary of Significant Accounting Policies
Schedule of Intangible Assets and Goodwill	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Goodwill – Branch acquisitions ​ $ 5,396 ​ $ 5,396 Deposit intangibles ​ ​ Boulevard Bank ​ 31 ​ 153 Valley Bank ​ 200 ​ 600 Fifth Third Bank ​ 1,317 ​ 1,949 ​ ​ 1,548 ​ 2,702 ​ ​ $ 6,944 ​ $ 8,098
Schedule of Earnings Per Share, Basic and Diluted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income and net income available to common shareholders ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common shares outstanding ​ 14,043 ​ 14,201 ​ 14,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average common share stock options outstanding ​ 61 ​ 129 ​ 128 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average diluted common shares ​ 14,104 ​ 14,330 ​ 14,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – basic ​ $ 4.22 ​ $ 5.18 ​ $ 4.75 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per common share – diluted ​ $ 4.21 ​ $ 5.14 ​ $ 4.71

Investments in Securities (Tabl

Investments in Securities (Tables)	12 Months Ended
	Dec. 31, 2020
Investments in Securities
Investment Securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ Cost Gains Losses Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 151,106 ​ $ 19,665 ​ $ 831 ​ $ 169,940 Agency collateralized mortgage obligations ​ 168,472 ​ 8,524 ​ 375 ​ 176,621 States and political subdivisions securities ​ 45,196 ​ 2,135 ​ 6 ​ 47,325 Small Business Administration securities ​ 20,033 ​ 1,014 ​ — ​ 21,047 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 384,807 ​ $ 31,338 ​ $ 1,212 ​ $ 414,933 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ Cost Gains Losses Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities $ 156,591 $ 8,716 $ 265 $ 165,042 Agency collateralized mortgage obligations ​ ​ 149,980 ​ ​ 2,891 ​ ​ 921 ​ ​ 151,950 States and political subdivisions securities ​ ​ 33,757 ​ ​ 1,368 ​ ​ — ​ ​ 35,125 Small Business Administration securities ​ ​ 22,132 ​ ​ — ​ ​ 74 ​ ​ 22,058 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 362,460 $ 12,975 $ 1,260 $ 374,175
Investments Classified by Contractual Maturity Date	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Fair ​ Cost Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ After one through five years ​ $ — ​ $ — After five through ten years ​ 8,672 ​ 9,251 After ten years ​ 36,524 ​ 38,074 Securities not due on a single maturity date ​ 339,611 ​ 367,608 ​ ​ $ 384,807 ​ $ 414,933
Schedule of Financial Instruments Owned and Pledged as Collateral	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ Amortized ​ Fair ​ Amortized ​ Fair ​ Cost Value Cost Value ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public deposits ​ $ 5,674 ​ $ 5,962 ​ $ 8,578 ​ $ 8,913 Collateralized borrowing accounts ​ 188,309 ​ 201,818 ​ 122,771 ​ 129,643 Other ​ 6,413 ​ 6,819 ​ 7,021 ​ 7,107 ​ ​ $ 200,396 ​ $ 214,599 ​ $ 138,370 ​ $ 145,663
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ ​ Fair ​ Unrealized ​ Fair ​ Unrealized ​ Fair ​ Unrealized Description of Securities Value Losses Value Losses Value Losses ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 10,279 ​ $ (831) ​ $ — ​ $ — ​ $ 10,279 ​ $ (831) Agency collateralized mortgage obligations ​ 12,727 ​ (375) ​ — ​ — ​ 12,727 ​ (375) Small Business Administration securities ​ — ​ — ​ — ​ — ​ — ​ — States and political subdivisions securities ​ 1,164 ​ (6) ​ — ​ — ​ 1,164 ​ (6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 24,170 ​ $ (1,212) ​ $ — ​ $ — ​ $ 24,170 ​ $ (1,212) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ ​ Fair ​ Unrealized ​ Fair ​ Unrealized ​ Fair ​ Unrealized Description of Securities Value Losses Value Losses Value Losses ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ — ​ $ — ​ $ 24,762 ​ $ (265) ​ $ 24,762 ​ $ (265) Agency collateralized mortgage obligations ​ ​ 69,372 ​ ​ (921) ​ ​ — ​ ​ — ​ ​ 69,372 ​ ​ (921) Small Business Administration securities ​ 22,058 ​ (74) ​ — ​ — ​ 22,058 ​ (74) States and political subdivisions securities ​ — ​ — ​ — ​ — ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 91,430 ​ $ (995) ​ $ 24,762 ​ $ (265) ​ $ 116,192 ​ $ (1,260)

Loans and Allowance for Loan _2

Loans and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2020
Tables/Schedules
Schedule of classes of loans	Classes of loans at December 31, 2020 and 2019, included: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) One- to four-family residential construction $ 42,793 $ 33,963 Subdivision construction ​ 30,894 ​ 16,088 Land development ​ 54,010 ​ 40,431 Commercial construction ​ 1,212,837 ​ 1,322,861 Owner occupied one- to four-family residential ​ 470,436 ​ 387,016 Non-owner occupied one- to four-family residential ​ 114,569 ​ 120,343 Commercial real estate ​ 1,553,677 ​ 1,494,172 Other residential ​ 1,021,145 ​ 866,006 Commercial business ​ 370,898 ​ 313,209 Industrial revenue bonds ​ 14,003 ​ 13,189 Consumer auto ​ 86,173 ​ 151,854 Consumer other ​ 40,762 ​ 46,720 Home equity lines of credit ​ 114,689 ​ 118,988 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 98,643 ​ 127,206 ​ ​ 5,225,529 ​ 5,052,046 Undisbursed portion of loans in process ​ (863,722) ​ (850,666) Allowance for loan losses ​ (55,743) ​ (40,294) Deferred loan fees and gains, net ​ (9,260) ​ (7,104) ​ ​ $ 4,296,804 ​ $ 4,153,982
Schedule of loans classified by aging analysis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Loans ​ ​ ​ ​ ​ ​ ​ ​ Over 90 ​ ​ ​ ​ ​ ​ ​ Total ​ > 90 Days Past ​ ​ 30-59 Days ​ 60-89 Days ​ Days ​ Total Past ​ ​ ​ ​ Loans ​ Due and ​ Past Due Past Due Past Due Due Current Receivable Still Accruing ​ ​ (In Thousands) One- to four-family residential construction ​ $ 1,365 ​ $ — ​ $ — ​ $ 1,365 ​ $ 41,428 ​ $ 42,793 ​ $ — Subdivision construction ​ — ​ — ​ — ​ — ​ 30,894 ​ 30,894 ​ — Land development ​ 20 ​ — ​ — ​ 20 ​ 53,990 ​ 54,010 ​ — Commercial construction ​ — ​ — ​ — ​ — ​ 1,212,837 ​ 1,212,837 ​ — Owner occupied one- to four- family residential ​ 1,379 ​ 113 ​ 1,502 ​ 2,994 ​ 467,442 ​ 470,436 ​ — Non-owner occupied one- to four-family residential ​ — ​ ​ — ​ ​ 69 ​ ​ 69 ​ ​ 114,500 ​ ​ 114,569 ​ — Commercial real estate ​ — ​ 79 ​ 587 ​ 666 ​ 1,553,011 ​ 1,553,677 ​ — Other residential ​ — ​ — ​ — ​ — ​ 1,021,145 ​ 1,021,145 ​ — Commercial business ​ — ​ — ​ 114 ​ 114 ​ 370,784 ​ 370,898 ​ — Industrial revenue bonds ​ — ​ — ​ — ​ — ​ 14,003 ​ 14,003 ​ — Consumer auto ​ 364 ​ 119 ​ 169 ​ 652 ​ 85,521 ​ 86,173 ​ — Consumer other ​ 443 ​ 7 ​ 94 ​ 544 ​ 40,218 ​ 40,762 ​ — Home equity lines of credit ​ 153 ​ 111 ​ 508 ​ 772 ​ 113,917 ​ 114,689 ​ — Loans acquired and accounted for under ASC 310-30, net of discounts ​ 1,662 ​ 641 ​ 3,843 ​ 6,146 ​ 92,497 ​ 98,643 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 5,386 ​ 1,070 ​ 6,886 ​ 13,342 ​ 5,212,187 ​ 5,225,529 ​ — Less: Loans acquired and accounted for under ASC 310-30, net of discounts ​ 1,662 ​ 641 ​ 3,843 ​ 6,146 ​ 92,497 ​ 98,643 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,724 ​ $ 429 ​ $ 3,043 ​ $ 7,196 ​ $ 5,119,690 ​ $ 5,126,886 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Loans ​ ​ ​ ​ ​ ​ ​ ​ Over 90 ​ ​ ​ ​ ​ ​ ​ Total ​ > 90 Days Past ​ ​ 30-59 Days ​ 60-89 Days ​ Days ​ Total Past ​ ​ ​ ​ Loans ​ Due and ​ Past Due Past Due Past Due Due Current Receivable Still Accruing ​ ​ (In Thousands) One- to four-family residential construction ​ $ — ​ $ — ​ $ — ​ $ — ​ $ 33,963 ​ $ 33,963 ​ $ — Subdivision construction ​ — ​ — ​ — ​ — ​ 16,088 ​ 16,088 ​ — Land development ​ — ​ 27 ​ — ​ 27 ​ 40,404 ​ 40,431 ​ — Commercial construction ​ 15,085 ​ — ​ — ​ 15,085 ​ 1,307,776 ​ 1,322,861 ​ — Owner occupied one- to four- family residential ​ 1,453 ​ 1,631 ​ 1,198 ​ 4,282 ​ 382,734 ​ 387,016 ​ — Non-owner occupied one- to four-family residential ​ 152 ​ — ​ 181 ​ 333 ​ 120,010 ​ 120,343 ​ — Commercial real estate ​ 549 ​ 119 ​ 632 ​ 1,300 ​ 1,492,872 ​ 1,494,172 ​ — Other residential ​ 376 ​ — ​ — ​ 376 ​ 865,630 ​ 866,006 ​ — Commercial business ​ 60 ​ — ​ 1,235 ​ 1,295 ​ 311,914 ​ 313,209 ​ — Industrial revenue bonds ​ — ​ — ​ — ​ — ​ 13,189 ​ 13,189 ​ — Consumer auto ​ 1,101 ​ 259 ​ 558 ​ 1,918 ​ 149,936 ​ 151,854 ​ — Consumer other ​ 278 ​ 233 ​ 198 ​ 709 ​ 46,011 ​ 46,720 ​ — Home equity lines of credit ​ 296 ​ — ​ 517 ​ 813 ​ 118,175 ​ 118,988 ​ — Loans acquired and accounted for under ASC 310-30, net of discounts ​ 2,177 ​ 709 ​ 6,191 ​ 9,077 ​ 118,129 ​ 127,206 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 21,527 ​ 2,978 ​ 10,710 ​ 35,215 ​ 5,016,831 ​ 5,052,046 ​ — Less: Loans acquired and accounted for under ASC 310-30, net of discounts ​ 2,177 ​ 709 ​ 6,191 ​ 9,077 ​ 118,129 ​ 127,206 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 19,350 ​ $ 2,269 ​ $ 4,519 ​ $ 26,138 ​ $ 4,898,702 ​ $ 4,924,840 ​ $ —
Schedule of Financing Receivable, Nonaccrual	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — ​ $ — Subdivision construction ​ — ​ — Land development ​ — ​ — Commercial construction ​ — ​ — Owner occupied one- to four-family residential ​ 1,502 ​ 1,198 Non-owner occupied one- to four-family residential ​ 69 ​ 181 Commercial real estate ​ 587 ​ 632 Other residential ​ — ​ — Commercial business ​ 114 ​ 1,235 Industrial revenue bonds ​ — ​ — Consumer auto ​ 169 ​ 558 Consumer other ​ 94 ​ 198 Home equity lines of credit ​ 508 ​ 517 ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,043 ​ $ 4,519
Schedule of Loans and Leases Receivable Allowance for Loan Losses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2020 ​ $ 4,339 ​ $ 5,153 ​ $ 24,334 ​ $ 3,076 ​ $ 1,355 ​ $ 2,037 ​ $ 40,294 Provision (benefit) charged to expense ​ 84 ​ 4,042 ​ 9,343 ​ 242 ​ 914 ​ 1,246 ​ 15,871 Losses charged off ​ (70) ​ — ​ (43) ​ (1) ​ (28) ​ (3,152) ​ (3,294) Recoveries ​ 183 ​ 180 ​ 73 ​ 204 ​ 149 ​ 2,083 ​ 2,872 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 ​ $ 4,536 ​ $ 9,375 ​ $ 33,707 ​ $ 3,521 ​ $ 2,390 ​ $ 2,214 ​ $ 55,743 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 90 ​ $ — ​ $ 445 ​ $ — ​ $ 14 ​ $ 164 ​ $ 713 Collectively evaluated for impairment ​ $ 4,382 ​ $ 9,282 ​ $ 32,937 ​ $ 3,378 ​ $ 2,331 ​ $ 2,040 ​ $ 54,350 Loans acquired and accounted for under ASC 310-30 ​ $ 64 ​ $ 93 ​ $ 325 ​ $ 143 ​ $ 45 ​ $ 10 ​ $ 680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 3,546 ​ $ — ​ $ 3,438 ​ $ — ​ $ 167 ​ $ 1,897 ​ $ 9,048 Collectively evaluated for impairment ​ $ 655,146 ​ $ 1,021,145 ​ $ 1,550,239 ​ $ 1,266,847 ​ $ 384,734 ​ $ 239,727 ​ $ 5,117,838 Loans acquired and accounted for under ASC 310-30 ​ $ 57,113 ​ $ 6,150 ​ $ 24,613 ​ $ 2,551 ​ $ 2,549 ​ $ 5,667 ​ $ 98,643 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2019 ​ $ 3,122 ​ $ 4,713 ​ $ 19,803 ​ $ 3,105 ​ $ 1,568 ​ $ 6,098 ​ $ 38,409 Provision (benefit) charged to expense ​ 1,625 ​ 603 ​ 4,651 ​ 22 ​ (309) ​ (442) ​ 6,150 Losses charged off ​ (534) ​ (189) ​ (144) ​ (101) ​ (371) ​ (6,723) ​ (8,062) Recoveries ​ 126 ​ 26 ​ 24 ​ 50 ​ 467 ​ 3,104 ​ 3,797 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 ​ $ 4,339 ​ $ 5,153 ​ $ 24,334 ​ $ 3,076 ​ $ 1,355 ​ $ 2,037 ​ $ 40,294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 198 ​ $ — ​ $ 517 ​ $ — ​ $ 13 ​ $ 201 ​ $ 929 Collectively evaluated for impairment ​ $ 3,973 ​ $ 5,101 ​ $ 23,570 ​ $ 2,940 ​ $ 1,306 ​ $ 1,814 ​ $ 38,704 Loans acquired and accounted for under ASC 310-30 ​ $ 168 ​ $ 52 ​ $ 247 ​ $ 136 ​ $ 36 ​ $ 22 ​ $ 661 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 2,960 ​ $ — ​ $ 4,020 ​ $ — ​ $ 1,286 ​ $ 2,001 ​ $ 10,267 Collectively evaluated for impairment ​ $ 554,450 ​ $ 866,006 ​ $ 1,490,152 ​ $ 1,363,292 ​ $ 325,112 ​ $ 315,561 ​ $ 4,914,573 Loans acquired and accounted for under ASC 310-30 ​ $ 74,562 ​ $ 5,334 ​ $ 29,158 ​ $ 3,606 ​ $ 3,356 ​ $ 11,190 ​ $ 127,206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ ​ One- to Four- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Family ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and ​ Other ​ Commercial ​ Commercial ​ Commercial ​ ​ ​ ​ ​ ​ Construction Residential Real Estate Construction Business Consumer Total ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for Loan Losses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2018 ​ $ 2,108 $ 2,839 $ 18,639 $ 1,767 $ 3,581 $ 7,558 $ 36,492 Provision (benefit) charged to expense ​ 742 ​ 1,982 ​ 1,094 ​ 1,031 ​ (1,613) ​ 3,914 7,150 Losses charged off ​ (62) ​ (525) ​ (102) ​ (87) ​ (1,155) ​ (9,425) (11,356) Recoveries ​ 334 ​ 417 ​ 172 ​ 394 ​ 755 ​ 4,051 6,123 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ $ 3,122 ​ $ 4,713 ​ $ 19,803 ​ $ 3,105 ​ $ 1,568 ​ $ 6,098 $ 38,409 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 694 ​ $ — ​ $ 613 ​ $ — ​ $ 309 ​ $ 425 $ 2,041 Collectively evaluated for impairment ​ $ 2,392 ​ $ 4,681 ​ $ 18,958 ​ $ 3,029 ​ $ 1,247 ​ $ 5,640 $ 35,947 Loans acquired and accounted for under ASC 310-30 ​ $ 36 ​ $ 32 ​ $ 232 ​ $ 76 ​ $ 12 ​ $ 33 $ 421 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ 6,116 ​ $ — ​ $ 3,501 ​ $ 14 ​ $ 1,844 ​ $ 2,464 $ 13,939 Collectively evaluated for impairment ​ $ 433,209 ​ $ 784,894 ​ $ 1,367,934 ​ $ 1,461,644 ​ $ 334,214 ​ $ 429,766 $ 4,811,661 Loans acquired and accounted for under ASC 310-30 ​ $ 93,841 ​ $ 12,790 ​ $ 33,620 ​ $ 4,093 ​ $ 4,347 ​ $ 18,960 $ 167,651
Schedule of impaired financing receivables	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction $ — $ — $ — $ — $ — Subdivision construction ​ 20 ​ 20 ​ — ​ 115 ​ 3 Land development ​ — ​ — ​ — ​ — ​ — Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 3,457 ​ 3,776 ​ 90 ​ 2,999 ​ 169 Non-owner occupied one- to four-family residential ​ 69 ​ 106 ​ — ​ 309 ​ 18 Commercial real estate ​ 3,438 ​ 3,472 ​ 445 ​ 3,736 ​ 135 Other residential ​ — ​ — ​ — ​ — ​ — Commercial business ​ 166 ​ 551 ​ 14 ​ 800 ​ 34 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 865 ​ 964 ​ 140 ​ 932 ​ 91 Consumer other ​ 403 ​ 552 ​ 19 ​ 298 ​ 47 Home equity lines of credit ​ 630 ​ 668 ​ 5 ​ 550 ​ 36 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 9,048 ​ $ 10,109 ​ $ 713 ​ $ 9,739 $ 533 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — ​ $ — ​ $ — ​ $ — $ — Subdivision construction ​ 251 ​ 251 ​ 96 ​ 277 ​ 9 Land development ​ — ​ — ​ — ​ 328 ​ 101 Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 2,300 ​ 2,423 ​ 82 ​ 2,598 ​ 131 Non-owner occupied one- to four-family residential ​ 409 ​ 574 ​ 20 ​ 954 ​ 43 Commercial real estate ​ 4,020 ​ 4,049 ​ 517 ​ 4,940 ​ 264 Other residential ​ — ​ — ​ — ​ — ​ — Commercial business ​ 1,286 ​ 1,771 ​ 13 ​ 1,517 ​ 81 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 1,117 ​ 1,334 ​ 181 ​ 1,128 ​ 125 Consumer other ​ 356 ​ 485 ​ 16 ​ 383 ​ 48 Home equity lines of credit ​ 528 ​ 548 ​ 4 ​ 362 ​ 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 10,267 ​ $ 11,435 ​ $ 929 ​ $ 12,487 $ 839 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2018 ​ December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Investment ​ Interest ​ ​ Recorded ​ Principal ​ Specific ​ in Impaired ​ Income ​ Balance Balance Allowance Loans Recognized ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ — $ — ​ $ — ​ $ — ​ $ — Subdivision construction ​ 318 ​ 318 ​ 105 ​ 321 ​ 17 Land development ​ 14 ​ 18 ​ — ​ 14 ​ 1 Commercial construction ​ — ​ — ​ — ​ — ​ — Owner occupied one- to four-family residential ​ 3,576 ​ 3,926 ​ 285 ​ 3,406 ​ 197 Non-owner occupied one- to four-family residential ​ 2,222 ​ 2,519 ​ 304 ​ 2,870 ​ 158 Commercial real estate ​ 3,501 ​ 3,665 ​ 613 ​ 6,216 ​ 337 Other residential ​ — ​ — ​ — ​ 1,026 ​ 20 Commercial business ​ 1,844 ​ 2,207 ​ 309 ​ 2,932 ​ 362 Industrial revenue bonds ​ — ​ — ​ — ​ — ​ — Consumer auto ​ 1,874 ​ 2,114 ​ 336 ​ 2,069 ​ 167 Consumer other ​ 479 ​ 684 ​ 72 ​ 738 ​ 59 Home equity lines of credit ​ 111 ​ 128 ​ 17 ​ 412 ​ 28 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 13,939 ​ $ 15,579 ​ $ 2,041 ​ $ 20,004 $ 1,346
Schedule of Financing Receivable, Troubled Debt Restructuring	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential one-to-four family ​ $ — ​ $ — ​ $ 1,030 ​ $ 1,030 Commercial real estate ​ — ​ — ​ 559 ​ 559 Commercial business ​ — ​ — ​ 22 ​ 22 Consumer ​ — ​ 16 ​ 1,951 ​ 1,967 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ — ​ $ 16 ​ $ 3,562 ​ $ 3,578 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer ​ $ — ​ $ 136 ​ $ — ​ $ 136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ — ​ $ 136 ​ $ — ​ $ 136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ Interest Only Term Combination Modification ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential one-to-four family ​ $ 1,348 ​ $ — ​ $ — ​ $ 1,348 Construction and land development ​ ​ — ​ ​ 31 ​ ​ — ​ ​ 31 Commercial construction ​ — ​ — ​ 106 ​ 106 Consumer ​ — ​ 535 ​ — ​ 535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,348 ​ $ 566 ​ $ 106 ​ $ 2,020
Schedule of financing receivable credit quality indicators	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Special ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Satisfactory Watch Mention Substandard Doubtful Total ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ 41,428 ​ $ 1,365 ​ $ — ​ $ — ​ $ — ​ $ 42,793 Subdivision construction ​ 30,874 ​ — ​ — ​ 20 ​ — ​ 30,894 Land development ​ 54,010 ​ — ​ — ​ — ​ — ​ 54,010 Commercial construction ​ 1,212,837 ​ — ​ — ​ — ​ — ​ 1,212,837 Owner occupied one- to-four-family residential ​ 467,855 ​ 216 ​ — ​ 2,365 ​ — ​ 470,436 Non-owner occupied one-to-four-family residential ​ 114,176 ​ 324 ​ — ​ 69 ​ — ​ 114,569 Commercial real estate ​ 1,498,031 ​ 52,208 ​ — ​ 3,438 ​ — ​ 1,553,677 Other residential ​ 1,017,648 ​ 3,497 ​ — ​ — ​ — ​ 1,021,145 Commercial business ​ 363,681 ​ 7,102 ​ — ​ 115 ​ — ​ 370,898 Industrial revenue bonds ​ 14,003 ​ — ​ — ​ — ​ — ​ 14,003 Consumer auto ​ 85,657 ​ 5 ​ — ​ 511 ​ — ​ 86,173 Consumer other ​ 40,514 ​ 2 ​ — ​ 246 ​ — ​ 40,762 Home equity lines of credit ​ 114,049 ​ 39 ​ — ​ 601 ​ — ​ 114,689 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 98,633 ​ — ​ — ​ 10 ​ — ​ 98,643 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 5,153,396 ​ $ 64,758 ​ $ — ​ $ 7,375 ​ $ — ​ $ 5,225,529 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Special ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Satisfactory Watch Mention Substandard Doubtful Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One- to four-family residential construction ​ $ 33,963 ​ $ — ​ $ — ​ $ — ​ $ — ​ $ 33,963 Subdivision construction ​ 16,061 ​ 27 ​ — ​ — ​ — ​ 16,088 Land development ​ 40,431 ​ — ​ — ​ — ​ — ​ 40,431 Commercial construction ​ 1,322,861 ​ — ​ — ​ — ​ — ​ 1,322,861 Owner occupied one- to-four-family residential ​ 385,001 ​ 26 ​ — ​ 1,989 ​ — ​ 387,016 Non-owner occupied one-to-four-family residential ​ 119,743 ​ 419 ​ — ​ 181 ​ — ​ 120,343 Commercial real estate ​ 1,458,400 ​ 32,063 ​ — ​ 3,709 ​ — ​ 1,494,172 Other residential ​ 866,006 ​ — ​ — ​ — ​ — ​ 866,006 Commercial business ​ 307,322 ​ 4,651 ​ — ​ 1,236 ​ — ​ 313,209 Industrial revenue bonds ​ 13,189 ​ — ​ — ​ — ​ — ​ 13,189 Consumer auto ​ 150,874 ​ 47 ​ — ​ 933 ​ — ​ 151,854 Consumer other ​ 46,294 ​ 92 ​ — ​ 334 ​ — ​ 46,720 Home equity lines of credit ​ 118,428 ​ 43 ​ — ​ 517 ​ — ​ 118,988 Loans acquired and accounted for under ASC 310-30, net of discounts ​ 127,192 ​ — ​ — ​ 14 ​ — ​ 127,206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 5,005,765 ​ $ 37,368 ​ $ — ​ $ 8,913 ​ $ — ​ $ 5,052,046
Schedule of related party transactions	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Balance, beginning of year ​ $ 15,240 ​ $ 29,017 New loans ​ 901 ​ 15,062 Payments ​ (2,673) ​ (28,839) ​ ​ ​ ​ ​ ​ ​ Balance, end of year ​ $ 13,468 ​ $ 15,240

FDIC-Acquired Loans and Loss _2

FDIC-Acquired Loans and Loss Sharing Agreements (Tables)	12 Months Ended
	Dec. 31, 2020
FDIC-Acquired Loans and Loss Sharing Agreements
Schedule of FDIC Indemnification Asset Policy	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sun Security ​ ​ ​ ​ ​ ​ ​ TeamBank Vantus Bank Bank InterBank Valley Bank ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ Gross loans receivable ​ $ 5,393 ​ $ 8,052 ​ $ 13,395 ​ $ 44,215 ​ $ 31,515 Balance of accretable discount due to change in expected losses ​ (97) ​ (35) ​ (180) ​ (1,079) ​ (612) Net carrying value of loans receivable ​ (5,266) ​ (8,004) ​ (13,111) ​ (42,057) ​ (30,204) Expected loss remaining ​ $ 30 ​ $ 13 ​ $ 104 ​ $ 1,079 ​ $ 699 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Gross loans receivable ​ $ 7,304 ​ $ 9,899 ​ $ 17,906 ​ $ 60,430 ​ $ 41,032 Balance of accretable discount due to change in expected losses ​ (159) ​ (89) ​ (374) ​ (5,143) ​ (1,803) Net carrying value of loans receivable ​ (7,118) ​ (9,797) ​ (17,392) ​ (54,442) ​ (38,452) Expected loss remaining ​ $ 27 ​ $ 13 ​ $ 140 ​ $ 845 ​ $ 777
Schedule of Impact of Adjustments of Acquired Loans on Financial Results	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Increase in accretable yield due to increased cash flow expectations ​ $ — ​ $ 12,323 ​ $ 5,202
Schedule of Impact of Acquired Loans on Financial Results	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income and net impact to pre-tax income ​ $ 5,574 ​ $ 7,431 ​ $ 5,134
Schedule Of Accretable Yield Changes For Acquired Loans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sun ​ ​ ​ ​ ​ ​ ​ TeamBank Vantus Bank Security Bank InterBank Valley Bank ​ ​ (In Thousands) Balance, January 1, 2018 ​ ​ 2,071 ​ ​ 1,850 ​ ​ 2,901 ​ ​ 5,074 ​ ​ 2,695 Accretion ​ (1,042) ​ (1,196) ​ (1,667) ​ (8,349) ​ (3,892) Reclassification from nonaccretable difference (1) ​ 327 ​ 778 ​ 1,008 ​ 8,269 ​ 4,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ 1,356 ​ 1,432 ​ 2,242 ​ 4,994 ​ 3,063 Accretion ​ (955) ​ (1,006) ​ (1,562) ​ (8,798) ​ (4,302) Reclassification from nonaccretable difference (1) ​ 756 ​ 697 ​ 1,268 ​ 12,081 ​ 5,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 ​ $ 1,157 ​ $ 1,123 ​ $ 1,948 ​ $ 8,277 ​ $ 4,578 Accretion ​ (479) ​ (831) ​ (1,046) ​ (6,791) ​ (3,005) Reclassification from nonaccretable difference (1) ​ 198 ​ 451 ​ 493 ​ 2,219 ​ 2,764 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 ​ $ 876 ​ $ 743 ​ $ 1,395 ​ $ 3,705 ​ $ 4,337 (1) Represents increases in estimated cash flows expected to be received from the acquired loan pools, primarily due to lower estimated credit losses. The numbers also include changes in expected accretion of the loan pools for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2020, totaling $198,000, $451,000, $493,000, $2.2 million and $2.8 million, respectively; TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2019, totaling $667,000, $480,000, $810,000, $3.9 million and $2.5 million, respectively; for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2018, totaling $312,000, $778,000, $756,000, $4.1 million and $3.5 million, respectively .

Other Real Estate Owned and R_2

Other Real Estate Owned and Repossessions (Tables)	12 Months Ended
	Dec. 31, 2020
Other Real Estate Owned and Repossessions
Schedule of Major classifications of other real estate owned	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) Foreclosed assets held for sale and repossessions ​ ​ One- to four-family construction ​ $ — ​ $ — Subdivision construction ​ 263 ​ 689 Land development ​ 250 ​ 1,816 Commercial construction ​ — ​ — One- to four-family residential ​ 111 ​ 601 Other residential ​ — ​ — Commercial real estate ​ — ​ — Commercial business ​ — ​ — Consumer ​ 153 ​ 545 ​ ​ 777 ​ 3,651 ​ ​ ​ ​ ​ Foreclosed assets related to FDIC acquisitions, net of discounts ​ 446 ​ 1,003 ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale and repossessions, net ​ 1,223 ​ 4,654 ​ ​ ​ ​ ​ ​ ​ Other real estate owned not acquired through foreclosure ​ 654 ​ 871 ​ ​ ​ ​ ​ ​ ​ Other real estate owned and repossessions ​ $ 1,877 ​ $ 5,525
Schedule of Expenses Applicable to Foreclosed Assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net gains on sales of other real estate owned and repossessions ​ $ (480) ​ $ (750) ​ $ (2,522) Valuation write-downs ​ 1,320 ​ 926 ​ 3,897 Operating expenses, net of rental income ​ 1,183 ​ 2,008 ​ 3,544 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,023 ​ $ 2,184 ​ $ 4,919

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Premises and Equipment
Schedule of major classification	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Land ​ $ 40,652 ​ $ 40,632 Buildings and improvements ​ 100,187 ​ 96,959 Furniture, fixtures and equipment ​ 59,226 ​ 56,986 Operating leases right of use asset ​ 8,536 ​ 8,668 ​ ​ 208,601 ​ 203,245 Less accumulated depreciation ​ 69,431 ​ 61,337 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 139,170 ​ $ 141,908
Schedule of calculated amounts of the right of use assets and lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At or For the Year Ended ​ ​ December 31, 2020 December 31, 2019 ​ ​ (In Thousands) Statement of Financial Condition ​ ​ ​ ​ Operating leases right of use asset ​ $ 8,536 ​ $ 8,668 Operating leases liability ​ $ 8,661 ​ $ 8,747 ​ ​ ​ ​ ​ ​ ​ Statement of Income ​ ​ ​ Operating lease costs classified as occupancy and equipment expense ​ $ 1,572 ​ $ 1,460 (includes short-term lease costs and amortization of right of use asset) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental Cash Flow Information ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ Operating cash flows from operating leases ​ $ 1,526 ​ $ 1,381 Right of use assets obtained in exchange for lease obligations: ​ ​ ​ Operating leases ​ $ 972 ​ $ 9,538
Schedule of Future Minimum Rental Payments for Operating Leases	​ ​ ​ ​ ​ 2021 $ 1,119 2022 ​ 1,116 2023 ​ 1,088 2024 ​ 1,005 2025 ​ 979 Thereafter ​ 4,926 ​ ​ ​ ​ Future lease payments expected ​ 10,233 ​ ​ ​ ​ Less interest portion of lease payments ​ (1,572) ​ ​ ​ ​ Lease liability ​ $ 8,661

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2020
Deposits
Schedule of Deposit Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Interest Rate 2020 2019 ​ ​ ​ ​ (In Thousands, Except Interest Rates) ​ ​ ​ ​ ​ ​ ​ ​ ​ Noninterest-bearing accounts — ​ $ 984,798 ​ $ 687,068 Interest-bearing checking and savings accounts 0.22% and 0.55% 2,141,313 ​ 1,551,929 ​ ​ ​ 3,126,111 ​ ​ 2,238,997 ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificate accounts 0% - 0.99% ​ 803,737 ​ 122,649 ​ 1% - 1.99% ​ 425,061 ​ 523,816 ​ 2% - 2.99% ​ 143,417 ​ 1,053,914 ​ 3% - 3.99% ​ 18,148 ​ 19,849 ​ 4% and above ​ 429 ​ 881 ​ ​ ​ 1,390,792 ​ ​ 1,721,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 4,516,903 ​ $ 3,960,106
Schedule of Maturities of certificates of deposit	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail Brokered Total ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 995,934 ​ $ 91,345 ​ $ 1,087,279 2022 ​ 175,913 ​ 13,751 ​ 189,664 2023 ​ 30,898 ​ 42,448 ​ 73,346 2024 ​ 14,647 ​ 11,200 ​ 25,847 2025 ​ 13,743 ​ — ​ 13,743 Thereafter ​ 913 ​ — ​ 913 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,232,048 ​ $ 158,744 ​ $ 1,390,792
Schedule of Interest Expense on Deposit Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Checking and savings accounts ​ $ 7,096 ​ $ 7,971 ​ $ 5,982 Certificate accounts ​ 25,453 ​ 37,723 ​ 22,149 Early withdrawal penalties ​ (118) ​ (124) ​ (174) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 32,431 ​ $ 45,570 ​ $ 27,957

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2020
Short-Term Borrowings
Schedule of short-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Notes payable – Community Development Equity Funds ​ $ 1,518 ​ $ 1,267 Other interest-bearing liabilities ​ — ​ 30,890 Overnight borrowings from the Federal Home Loan Bank ​ — ​ 196,000 Securities sold under reverse repurchase agreements ​ 164,174 ​ 84,167 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 165,692 ​ $ 312,324
Schedule of repurchase agreements	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ Overnight and ​ Overnight and ​ ​ Continuous ​ Continuous ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Mortgage-backed securities – GNMA, FNMA, FHLMC ​ $ 164,174 ​ $ 84,167

Subordinated Debentures Issue_2

Subordinated Debentures Issued to Capital Trusts (Tables)	12 Months Ended
	Dec. 31, 2020
Subordinated Debentures Issued to Capital Trusts
Schedule of Subordinated Debentures Issued to Capital Trusts	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Subordinated debentures ​ $ 25,774 $ 25,774

Subordinated Notes (Tables)

Subordinated Notes (Tables)	12 Months Ended
	Dec. 31, 2020
Subordinated Notes
Schedule of subordinated notes	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Subordinated notes ​ $ 150,000 ​ $ 75,000 Less: unamortized debt issuance costs ​ 1,603 ​ 724 ​ ​ $ 148,397 ​ $ 74,276

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Taxes
Schedule of provision for income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Taxes currently payable ​ $ 25,259 ​ $ 15,375 ​ $ 19,291 Deferred income taxes (benefit) ​ (11,480) ​ 1,074 ​ (4,450) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income taxes ​ $ 13,779 ​ $ 16,449 ​ $ 14,841
Schedule of deferred tax assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (In Thousands) Deferred tax assets ​ ​ Allowance for loan losses ​ $ 12,711 ​ $ 9,188 Interest on nonperforming loans ​ 142 ​ 161 Accrued expenses ​ 894 ​ 821 Write-down of foreclosed assets ​ 131 ​ 185 Write-down of fixed assets ​ 114 ​ 50 Income recognized for tax in excess of book ​ 8,830 ​ — Partnership tax credits ​ 11 ​ 732 Deferred income ​ 885 ​ 509 Difference in basis for acquired assets and liabilities ​ ​ 1,532 ​ ​ 2,540 ​ ​ 25,250 ​ 14,186 ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities ​ ​ Tax depreciation in excess of book depreciation ​ (5,988) ​ (5,986) FHLB stock dividends ​ (368) ​ (817) Prepaid expenses ​ (898) ​ (891) Unrealized gain on available-for-sale securities ​ (6,869) ​ (2,671) Unrealized gain on cash flow derivatives ​ (8,830) ​ (6,853) Other ​ (258) ​ (233) ​ ​ (23,211) ​ (17,451) ​ ​ ​ ​ ​ ​ ​ Net deferred tax asset (liability) ​ $ 2,039 ​ $ (3,265)
Schedule of effective income tax rate reconciliation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Tax at statutory rate 21.0 % 21.0 % 21.0 % Nontaxable interest and dividends (0.5) (0.5) (0.8) ​ Tax credits (3.8) (3.6) (3.4) ​ State taxes 1.4 1.3 1.1 ​ Other 0.8 0.1 0.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 18.9 % 18.3 % 18.1 %

Disclosures About Fair Value _2

Disclosures About Fair Value of Financial Instruments - Schedule Of Financial Instruments Fair Value (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosures About Fair Value of Financial Instruments
Schedule of Fair Value, Assets Measured on Recurring Basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Markets ​ Other ​ Significant ​ ​ ​ ​ ​ for Identical ​ Observable ​ Unobservable ​ ​ ​ Assets Inputs ​ Inputs ​ Fair Value (Level 1) (Level 2) (Level 3) ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 169,940 ​ $ — ​ $ 169,940 ​ $ — Agency collateralized mortgage obligations ​ 176,621 ​ — ​ 176,621 ​ — States and political subdivisions securities ​ 47,325 ​ — ​ 47,325 ​ — Small Business Administration securities ​ 21,047 ​ — ​ 21,047 ​ — Interest rate derivative asset ​ 5,062 ​ — ​ 5,062 ​ — Interest rate derivative liability ​ (5,454) ​ — ​ (5,454) ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Agency mortgage-backed securities ​ $ 165,042 ​ $ — ​ $ 165,042 ​ $ — Agency collateralized mortgage obligations ​ 151,950 ​ — ​ 151,950 ​ — States and political subdivisions securities ​ ​ 35,125 ​ ​ — ​ ​ 35,125 ​ ​ — Small Business Administration securities ​ 22,058 ​ — ​ 22,058 ​ — Interest rate derivative asset ​ 31,476 ​ — ​ 31,476 ​ — Interest rate derivative liability ​ (1,547) ​ — ​ (1,547) ​ —
Schedule of Fair Value, Assets and Liabilities Measured on Nonrecurring Basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Markets ​ Other ​ Significant ​ ​ ​ for Identical ​ Observable ​ Unobservable ​ ​ ​ Assets Inputs ​ Inputs ​ Fair Value (Level 1) (Level 2) (Level 3) ​ (In Thousands) December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 1,759 ​ $ — ​ $ — ​ $ 1,759 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale ​ $ 945 ​ $ — ​ $ — ​ $ 945 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 635 ​ $ — ​ $ — ​ $ 635 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreclosed assets held for sale ​ $ 1,112 ​ $ — ​ $ — ​ $ 1,112
Schedule Of Financial Instruments Fair Value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ Carrying ​ Fair ​ Hierarchy ​ Carrying ​ Fair ​ Hierarchy ​ Amount Value Level Amount Value Level ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 563,729 ​ $ 563,729 1 ​ $ 220,155 ​ $ 220,155 1 Mortgage loans held for sale ​ 17,780 ​ 17,780 2 ​ 9,242 ​ 9,242 2 Loans, net of allowance for loan losses ​ 4,296,804 ​ 4,303,909 3 ​ 4,153,982 ​ 4,129,984 3 Accrued interest receivable ​ 12,793 ​ 12,793 3 ​ 13,530 ​ 13,530 3 Investment in FHLB stock and other assets ​ 9,806 ​ 9,806 3 ​ 13,473 ​ 13,473 3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deposits ​ 4,516,903 ​ 4,523,586 3 ​ 3,960,106 ​ 3,963,875 3 Short-term borrowings ​ 165,692 ​ 165,692 3 ​ 312,324 ​ 312,324 3 Subordinated debentures ​ 25,774 ​ 25,774 3 ​ 25,774 ​ 25,774 3 Subordinated notes ​ 148,397 ​ 157,032 2 ​ 74,276 ​ 76,875 2 Accrued interest payable ​ 2,594 ​ 2,594 3 ​ 4,250 ​ 4,250 3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized financial instruments (net of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commitments to originate loans ​ — ​ — 3 ​ — ​ — 3 Letters of credit ​ 84 ​ 84 3 ​ 109 ​ 109 3 Lines of credit ​ — ​ — 3 ​ — ​ — 3

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2020
Derivatives and Hedging Activities
Schedule of fair value of derivative Instruments and location in statements of financials	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location in ​ Fair Value ​ ​ Consolidated Statements ​ December 31, ​ December 31, ​ ​ of Financial Condition 2020 2019 ​ ​ ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives designated as hedging instruments ​ ​ ​ Interest rate swap ​ Prepaid expenses and other assets ​ $ — ​ $ 30,056 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivatives designated as hedging instruments ​ ​ ​ $ — ​ $ 30,056 ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets ​ ​ Interest rate products Prepaid expenses and other assets ​ $ 5,062 ​ $ 1,420 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivatives not designated as hedging instruments ​ ​ ​ $ 5,062 ​ $ 1,420 ​ ​ ​ Derivative Liabilities ​ ​ Interest rate products Accrued expenses and other liabilities ​ $ 5,454 ​ $ 1,547 ​ ​ ​ Total derivatives not designated as hedging instruments ​ ​ ​ $ 5,454 ​ $ 1,547 ​
Schedule of effect of cash flow hedge accounting on statements of comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Gain ​ ​ Recognized in AOCI ​ ​ Year Ended December 31 Cash Flow Hedges 2020 2019 2018 ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap, net of income taxes ​ $ 6,691 ​ $ 13,857 $ 9,345 ​
Schedule of effect of cash flow hedge accounting on statements of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31 Cash Flow Hedges ​ 2020 ​ 2019 ​ 2018 ​ ​ Interest ​ Interest ​ Interest ​ Interest ​ Interest ​ Interest ​ Income Expense Income ​ Expense ​ Income ​ Expense ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap, net of income taxes ​ $ 7,676 ​ $ — ​ $ 3,082 ​ $ — ​ $ 673 ​ $ —

Additional Cash Flow Informat_2

Additional Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2020
Additional Cash Flow Information
Schedule of Cash Flow, Supplemental Disclosures	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) Noncash Investing and Financing Activities ​ ​ ​ ​ ​ ​ Real estate acquired in settlement of loans ​ $ 1,707 ​ $ 12,729 ​ $ 12,044 Sale and financing of foreclosed assets ​ 625 ​ 1,340 ​ 2,578 Conversion of premises and equipment to foreclosed assets ​ 80 ​ 1,135 ​ — Dividends declared but not paid ​ 4,676 ​ 4,849 ​ 4,528 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional Cash Payment Information ​ ​ ​ Interest paid ​ 42,221 ​ 53,922 ​ 37,091 Income taxes paid ​ 18,755 ​ 5,719 ​ 2,569

Stock Compensation Plans (Table

Stock Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Stock Compensation Plans
Schedule of Share-based Compensation, Stock Options, Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Weighted ​ ​ Available ​ Under ​ Average ​ ​ to Grant ​ Option ​ Exercise Price ​ ​ ​ ​ ​ ​ ​ ​ Balance, January 1, 2018 ​ 77,512 ​ 682,799 ​ $ 38.860 Granted from 2013 Plan (1,000) 1,000 ​ 52.500 Exercised — (81,940) ​ 27.597 Forfeited from 2013 Plan 13,773 (13,773) ​ 45.692 Termination of 2013 Plan (90,285) — ​ ​ ​ ​ — ​ 588,086 ​ ​ ​ Available to grant from 2018 Plan ​ 800,000 ​ — ​ ​ ​ Granted from 2018 Plan ​ (185,750) ​ 185,750 ​ ​ 55.297 Forfeited from current plan(s) ​ 600 ​ (600) ​ ​ 55.000 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 614,850 773,236 ​ 43.886 Granted from 2018 Plan (186,400) 186,400 ​ 60.086 Exercised — (125,894) ​ 33.031 Forfeited from terminated plan(s) — (17,424) ​ 44.163 Forfeited from current plan(s) 8,450 (8,450) ​ 55.000 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2019 436,900 807,868 ​ 49.139 Granted from 2018 Plan (196,350) 196,350 ​ 41.740 Exercised — (21,436) ​ 33.805 Forfeited from terminated plan(s) — (6,875) ​ 38.849 Forfeited from current plan(s) 4,800 (4,800) ​ 57.513 ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2020 245,350 971,107 ​ $ 48.079
Schedule of Fair Value Option Pricing Model Assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expected dividends per share ​ $ 1.36 ​ $ 1.36 ​ $ 1.27 Risk-free interest rate ​ 0.35 % ​ 1.59 % ​ 2.86 % Expected life of options ​ 5 years ​ ​ 5 years ​ ​ 5 years ​ Expected volatility ​ 29.32 % ​ 25.15 % ​ 17.61 % Weighted average fair value of options granted during year ​ $ 7.30 ​ $ 11.20 ​ $ 8.30 ​
Schedule of Share-based Compensation, Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ Average ​ Remaining ​ ​ ​ ​ Exercise ​ Contractual ​ Options Price Term ​ ​ ​ ​ ​ ​ ​ Options outstanding, January 1, 2020 807,868 ​ 49.139 7.54 years Granted 196,350 ​ 41.740 ​ Exercised (21,436) ​ 30.805 ​ Forfeited (11,675) ​ 46.523 ​ Options outstanding, December 31, 2020 971,107 ​ 48.079 7.23 years ​ ​ ​ ​ ​ ​ ​ Options exercisable, December 31, 2020 363,695 ​ 42.583 4.95 years
Schedule of Nonvested Share Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ Exercise ​ Grant Date ​ Options Price Fair Value ​ ​ ​ ​ ​ ​ ​ Nonvested options, January 1, 2020 552,377 ​ 54.610 ​ 9.509 Granted 196,350 ​ 41.740 ​ 7.296 Vested this period (134,140) ​ 50.441 ​ 8.662 Nonvested options forfeited (7,175) ​ 54.655 ​ 9.501 ​ ​ ​ ​ ​ ​ ​ Nonvested options, December 31, 2020 607,412 ​ 51.370 ​ 8.981
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Options Exercisable ​ ​ ​ ​ Average ​ Weighted ​ ​ ​ Weighted ​ ​ ​ ​ Remaining ​ Average ​ ​ ​ Average ​ ​ Number ​ Contractual ​ Exercise ​ Number ​ Exercise Range of Exercise Prices Outstanding Term Price Exercisable Price ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $16.810 to 29.640 64,043 2.16 years ​ $ 25.598 64,043 ​ $ 25.598 $32.590 to 38.610 62,056 3.62 years ​ 33.001 61,181 ​ 32.921 $41.300 to 47.800 282,357 8.56 years ​ 41.613 59,816 ​ 41.335 $50.710 to 52.500 204,251 6.11 years ​ 51.656 133,496 ​ 51.415 $55.000 to 60.150 358,400 8.35 years ​ 57.762 45,159 ​ 55.306 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 971,107 7.23 years ​ 48.079 363,695 ​ 42.583

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ Net unrealized gain on available-for-sale securities ​ $ 30,126 ​ $ 11,715 ​ ​ ​ ​ ​ ​ ​ Net unrealized gain on derivatives used for cash flow hedges ​ 38,724 ​ 30,056 ​ ​ 68,850 ​ 41,771 ​ ​ ​ ​ ​ ​ ​ Tax effect ​ (15,699) ​ (9,525) ​ ​ ​ ​ ​ ​ ​ Net-of-tax amount ​ $ 53,151 ​ $ 32,246
Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts Reclassified ​ ​ ​ from AOCI ​ Affected Line Item in the ​ 2020 2019 2018 Statements of Income ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized gains/(losses) on available- for-sale securities ​ $ 78 ​ $ (62) ​ $ 2 Net realized gains on available-for-sale securities (total reclassified amount before tax) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in fair value of cash flow hedge ​ ​ 6,764 ​ ​ — ​ ​ — ​ Amortization of realized gain on termination of cash flow hedge (total reclassification amount before tax) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income taxes ​ (1,559) ​ 14 ​ — Tax (expense) benefit ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications out of AOCI ​ $ 5,283 ​ $ 48 ​ $ 2

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2020
Regulatory Matters
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ To Be Well ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Capitalized Under ​ ​ ​ ​ ​ ​ ​ For Capital ​ Prompt Corrective ​ ​ Actual ​ Adequacy Purposes ​ Action Provisions ​ Amount Ratio Amount Ratio Amount Ratio ​ ​ (Dollars In Thousands) As of December 31, 2020 ​ ​ ​ ​ Total capital ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 800,388 17.2 % $ 373,132 8.0 % ​ N/A N/A ​ Great Southern Bank ​ $ 694,047 14.9 % $ 373,058 8.0 % $ 466,322 10.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 594,645 12.7 % $ 279,849 6.0 % N/A N/A ​ Great Southern Bank ​ $ 638,304 13.7 % $ 279,793 6.0 % $ 373,058 8.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I leverage capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 594,645 10.9 % $ 217,223 4.0 % N/A N/A ​ Great Southern Bank ​ $ 638,304 11.8 % $ 217,170 4.0 % $ 271,463 5.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common equity Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 569,645 12.2 % $ 209,887 4.5 % N/A N/A ​ Great Southern Bank ​ $ 638,304 13.7 % $ 209,845 4.5 % $ 303,109 6.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Total capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 698,085 15.0 % $ 372,387 8.0 % N/A N/A ​ Great Southern Bank ​ $ 650,280 14.0 % $ 372,316 8.0 % $ 465,395 10.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 582,791 12.5 % $ 279,290 6.0 % N/A N/A ​ Great Southern Bank ​ $ 609,986 13.1 % $ 279,237 6.0 % $ 372,316 8.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier I leverage capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 582,791 11.8 % $ 198,320 4.0 % N/A N/A ​ Great Southern Bank ​ $ 609,986 12.3 % $ 198,010 4.0 % $ 247,512 5.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common equity Tier I capital ​ ​ ​ ​ ​ ​ ​ Great Southern Bancorp, Inc. ​ $ 557,791 12.0 % $ 209,468 4.5 % N/A N/A ​ Great Southern Bank ​ $ 609,986 13.1 % $ 209,428 4.5 % $ 302,507 6.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Summary of Unaudited Quarterl_2

Summary of Unaudited Quarterly Operating Results (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of Unaudited Quarterly Operating Results
Summary of Unaudited Quarterly Operating Results	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 57,474 ​ $ 54,011 ​ $ 53,599 ​ $ 52,619 Interest expense ​ 12,536 ​ 10,556 ​ 9,431 ​ 8,042 Provision for loan losses ​ 3,871 ​ 6,000 ​ 4,500 ​ 1,500 Net realized gains on available-for-sale securities ​ — ​ 78 ​ — ​ — Noninterest income ​ 7,367 ​ 8,261 ​ 9,466 ​ 9,956 Noninterest expense ​ 30,815 ​ 29,349 ​ 31,988 ​ 31,073 Provision for income taxes ​ 2,751 ​ 3,164 ​ 3,692 ​ 4,172 Net income available to common shareholders ​ 14,868 ​ 13,203 ​ 13,454 ​ 17,788 Earnings per common share – diluted ​ 1.04 ​ 0.93 ​ 0.96 ​ 1.28 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 57,358 ​ $ 58,723 ​ $ 60,187 ​ $ 58,726 Interest expense ​ 12,753 ​ 13,802 ​ 14,263 ​ 13,784 Provision for loan losses ​ 1,950 ​ 1,600 ​ 1,950 ​ 650 Net realized gains (losses) on available-for-sale securities ​ 10 ​ — ​ — ​ (72) Noninterest income ​ 7,450 ​ 7,157 ​ 8,655 ​ 7,695 Noninterest expense ​ 28,495 ​ 28,383 ​ 28,725 ​ 29,535 Provision for income taxes ​ 3,998 ​ 3,720 ​ 4,172 ​ 4,559 Net income available to common shareholders ​ 17,612 ​ 18,375 ​ 19,732 ​ 17,893 Earnings per common share – diluted ​ 1.23 ​ 1.28 ​ 1.38 ​ 1.24 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ Three Months Ended ​ March 31 June 30 September 30 December 31 ​ ​ (In Thousands, Except Per Share Data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest income ​ $ 46,882 ​ $ 49,943 ​ $ 52,982 ​ $ 56,142 Interest expense ​ 7,444 ​ 8,731 ​ 9,997 ​ 11,585 Provision for loan losses ​ 1,950 ​ 1,950 ​ 1,300 ​ 1,950 Net realized gains on available-for-sale securities ​ — ​ — ​ 2 ​ — Noninterest income ​ 6,935 ​ 7,459 ​ 14,604 ​ 7,220 Noninterest expense ​ 28,312 ​ 29,915 ​ 28,309 ​ 28,774 Provision for income taxes ​ 2,645 ​ 2,967 ​ 5,464 ​ 3,765 Net income available to common shareholders ​ 13,466 ​ 13,839 ​ 22,516 ​ 17,288 Earnings per common share – diluted ​ 0.95 ​ 0.97 ​ 1.57 ​ 1.21

Condensed Parent Company Stat_2

Condensed Parent Company Statements (Tables)	12 Months Ended
	Dec. 31, 2020
Condensed Parent Company Statements
Schedule of condensed financial condition	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (In Thousands) Statements of Financial Condition ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets ​ ​ ​ ​ ​ ​ Cash ​ $ 111,250 ​ $ 58,726 Investment in subsidiary bank ​ 698,398 ​ 650,329 Deferred and accrued income taxes ​ 157 ​ 111 Prepaid expenses and other assets ​ 883 ​ 868 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 810,688 ​ $ 710,034 ​ ​ ​ ​ ​ ​ ​ Liabilities and Stockholders’ Equity ​ ​ ​ ​ Accounts payable and accrued expenses ​ $ 6,776 ​ $ 6,918 Subordinated debentures issued to capital trust ​ 25,774 ​ 25,774 Subordinated notes ​ 148,397 ​ 74,276 Common stock ​ 138 ​ 143 Additional paid-in capital ​ 35,004 ​ 33,510 Retained earnings ​ 541,448 ​ 537,167 Accumulated other comprehensive income ​ 53,151 ​ 32,246 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 810,688 ​ $ 710,034
Schedule of condensed statements of income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income ​ ​ ​ Dividends from subsidiary bank ​ $ 40,000 ​ $ 32,000 ​ $ 34,000 Other income ​ 5 ​ — ​ — Loss on other investments ​ — ​ (23) ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 40,005 ​ 31,977 ​ 34,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expense ​ ​ ​ ​ ​ ​ Operating expenses ​ 2,197 ​ 2,044 ​ 1,793 Interest expense ​ 7,459 ​ 5,397 ​ 5,050 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9,656 ​ 7,441 ​ 6,843 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income tax and equity in undistributed earnings of subsidiaries ​ 30,349 ​ 24,536 ​ 27,157 Credit for income taxes ​ (1,800) ​ (1,381) ​ (1,204) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before equity in earnings of subsidiaries ​ 32,149 ​ 25,917 ​ 28,361 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity in undistributed earnings of subsidiaries ​ 27,164 ​ 47,695 ​ 38,748 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109
Schedule of condensed statements of cashflows	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Cash Flows ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Activities ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 Items not requiring (providing) cash ​ ​ ​ ​ ​ ​ Equity in undistributed earnings of subsidiary ​ (27,164) ​ (47,695) ​ (38,748) Compensation expense for stock option grants ​ 1,153 ​ 922 ​ 737 Amortization of interest rate derivative and deferred costs on subordinated notes ​ 608 ​ 434 ​ 154 Loss on other investments ​ — ​ 23 ​ — Changes in ​ ​ ​ ​ ​ ​ Prepaid expenses and other assets ​ (15) ​ (3) ​ 13 Accounts payable and accrued expenses ​ 31 ​ 226 ​ 182 Income taxes ​ (46) ​ 300 ​ (278) Net cash provided by operating activities ​ 33,880 ​ 27,819 ​ 29,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investing Activities ​ ​ ​ Return of principal - other investments ​ — ​ 2 ​ — Net cash provided by investing activities ​ — ​ 2 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financing Activities ​ ​ ​ Purchases of the Company’s common stock ​ (22,104) ​ (849) ​ (903) Proceeds from issuance of subordinated notes ​ ​ 73,513 ​ ​ — ​ ​ — Dividends paid ​ (33,426) ​ (29,052) ​ (15,819) Stock options exercised ​ 661 ​ 4,158 ​ 2,224 Net cash used in financing activities ​ 18,644 ​ (25,743) ​ (14,498) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Increase in Cash ​ 52,524 ​ 2,078 ​ 14,671 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash, Beginning of Year ​ 58,726 ​ 56,648 ​ 41,977 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash, End of Year ​ $ 111,250 ​ $ 58,726 ​ $ 56,648 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional Cash Payment Information ​ ​ ​ ​ ​ ​ Interest paid ​ $ 7,349 ​ $ 5,424 ​ $ 5,001
Schedule of condensed statements of comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 ​ ​ (In Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Statements of Comprehensive Income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Income ​ $ 59,313 ​ $ 73,612 ​ $ 67,109 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income of subsidiaries ​ 20,905 ​ 22,619 ​ 8,114 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive Income ​ $ 80,218 ​ $ 96,231 ​ $ 75,223

Nature of Operations and Summ_4

Nature of Operations and Summary of Significant Accounting Policies - Impairment or Disposal of Long-Lived Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations and Summary of Significant Accounting Policies
Asset Impairment Charges	$ 0	$ 0	$ 0

Nature of Operations and Summ_5

Nature of Operations and Summary of Significant Accounting Policies - Schedule of Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Intangible assets, amortization period	7 years
Goodwill -- Branch acquisition	$ 5,396	$ 5,396
Finite-Lived Core Deposits, Gross	1,548	2,702
Intangible Assets, Net (Including Goodwill), Total	6,944	8,098
Boulevard Bank
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	31	153
Valley Bank
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	200	600
Fifth Third Bank
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 1,317	$ 1,949

Nature of Operations and Summ_6

Nature of Operations and Summary of Significant Accounting Policies - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations and Summary of Significant Accounting Policies
Net income and net income available to common shareholders	$ 59,313	$ 73,612	$ 67,109
Average common shares outstanding	14,043	14,201	14,132
Average common share stock options outstanding	61	129	128
Average diluted common shares	14,104	14,330	14,260
Earnings per common share - basic	$ 4.22	$ 5.18	$ 4.75
Earnings per common share - diluted	$ 4.21	$ 5.14	$ 4.71

Nature of Operations and Summ_7

Nature of Operations and Summary of Significant Accounting Policies - Options to Purchase Shares of Common Stock (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations and Summary of Significant Accounting Policies
Options to purchase shares of common stock outstanding not included in computation of diluted earnings per share because exercise price greater than average market price	758,901	201,400	424,833

Nature of Operations and Summ_8

Nature of Operations and Summary of Significant Accounting Policies - Stock Compensation Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations and Summary of Significant Accounting Policies
Share-based Payment Arrangement, Expense	$ 1,200,000	$ 922,000	$ 737,000

Nature of Operations and Summ_9

Nature of Operations and Summary of Significant Accounting Policies - Restrictions on Cash and Due From Banks (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Nature of Operations and Summary of Significant Accounting Policies
Federal Reserve Bank Reserve Fund	$ 0	$ 69,400,000

Nature of Operations and Sum_10

Nature of Operations and Summary of Significant Accounting Policies - New Accounting Pronouncements, Policy (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Impairment of goodwill and intangible assets	$ 0
Accounting Standards Update 2016-13 [Member] | SEC Schedule, 12-09, Allowance, Credit Loss
New accounting pronouncement or change in accounting principle effect of adoption	12,000,000
Accounting Standards Update 2016-13 [Member] | Liability for potential losses related to unfunded portion of loans and commitments Member
New accounting pronouncement or change in accounting principle effect of adoption	8,000,000
Accounting Standards Update 2016-13 [Member] | After-tax effect on retained earnings Member
New accounting pronouncement or change in accounting principle effect of adoption	$ 13,000,000

Investments in Securities - Inv

Investments in Securities - Investment Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale Securities
Available For Sale Securities Amortized Cost Amount	$ 384,807	$ 362,460
Available-for-sale Securities, Gross Unrealized Gain	31,338	12,975
Available-for-sale Securities, Gross Unrealized Loss	1,212	1,260
Available for Sale Securities Fair Value	414,933	374,175
Agency mortgage-backed securities
Available For Sale Securities Amortized Cost Amount	151,106	156,591
Available-for-sale Securities, Gross Unrealized Gain	19,665	8,716
Available-for-sale Securities, Gross Unrealized Loss	831	265
Available for Sale Securities Fair Value	169,940	165,042
Agency collateralized mortgage obligations
Available For Sale Securities Amortized Cost Amount	168,472	149,980
Available-for-sale Securities, Gross Unrealized Gain	8,524	2,891
Available-for-sale Securities, Gross Unrealized Loss	375	921
Available for Sale Securities Fair Value	176,621	151,950
States and political subdivisions securities
Available For Sale Securities Amortized Cost Amount	45,196	33,757
Available-for-sale Securities, Gross Unrealized Gain	2,135	1,368
Available-for-sale Securities, Gross Unrealized Loss	6
Available for Sale Securities Fair Value	47,325	35,125
Small Business Administration securities
Available For Sale Securities Amortized Cost Amount	20,033	22,132
Available-for-sale Securities, Gross Unrealized Gain	1,014
Available-for-sale Securities, Gross Unrealized Loss		74
Available for Sale Securities Fair Value	$ 21,047	$ 22,058

Investments in Securities - Add

Investments in Securities - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Securities classified as held to maturity	$ 0	$ 0
Fair Value of Debt Securities Reported Less Than Their Historical Cost	$ 24.2	$ 116.2
Debt Securities Reported Less Than Their Historical Cost Percent of Investment Portfolio	5.80%	31.10%
Fixed rates of interest
Marketable Securities [Line Items]
Agency collateralized mortgage obligations	$ 156.8
Mortgage Backed Securities	169.9
Variable rates of interest
Marketable Securities [Line Items]
Agency collateralized mortgage obligations	19.8
Federal National Mortgage Association Certificates and Obligations (FNMA)
Marketable Securities [Line Items]
Agency collateralized mortgage obligations	52.9
Agency mortgage-backed securities	156.6
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Marketable Securities [Line Items]
Agency collateralized mortgage obligations	17.9
Agency mortgage-backed securities	10.3
Government National Mortgage Association Certificates and Obligations (GNMA)
Marketable Securities [Line Items]
Agency collateralized mortgage obligations	105.8
Agency mortgage-backed securities	$ 3

Investments in Securities - I_2

Investments in Securities - Investments Classified by Contractual Maturity Date (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Investments in Securities
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10	$ 8,672
Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10	9,251
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10	36,524
Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10	38,074
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	339,611
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	367,608
Available For Sale Securities Amortized Cost of Contractual Maturities	384,807
Available For Sale Securities Fair Value of Contractual Maturities	$ 414,933

Investments in Securities - Sch

Investments in Securities - Schedule of Financial Instruments Owned and Pledged as Collateral (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Public deposits
Marketable Securities [Line Items]
Securities Owned and Pledged As Collateral Amortized Cost	$ 5,674	$ 8,578
Security Owned and Pledged as Collateral, Fair Value	5,962	8,913
Collateralized borrowing accounts
Marketable Securities [Line Items]
Securities Owned and Pledged As Collateral Amortized Cost	188,309	122,771
Security Owned and Pledged as Collateral, Fair Value	201,818	129,643
Other
Marketable Securities [Line Items]
Securities Owned and Pledged As Collateral Amortized Cost	6,413	7,021
Security Owned and Pledged as Collateral, Fair Value	6,819	7,107
Securities Pledged as Collateral
Marketable Securities [Line Items]
Securities Owned and Pledged As Collateral Amortized Cost	200,396	138,370
Security Owned and Pledged as Collateral, Fair Value	$ 214,599	$ 145,663

Investments in Securities - Unr

Investments in Securities - Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Collateralized Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 10,279
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(831)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		$ 24,762
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(265)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	10,279	24,762
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(831)	(265)
Agency collateralized mortgage obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	12,727	69,372
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(375)	(921)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	12,727	69,372
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(375)	(921)
States and political subdivisions securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,164
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,164
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(6)
Unrealized Losses and Estimated Fair Value
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	24,170	91,430
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,212)	(995)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		24,762
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(265)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	24,170	116,192
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,212)	(1,260)
Small Business Administration securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		22,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(74)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		22,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (74)

Investments in Securities - Oth

Investments in Securities - Other than temporary impairment securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in Securities
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	$ 0	$ 0	$ 0

Investments in Securities - Cre

Investments in Securities - Credit Losses Recognized on Investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	$ 0	$ 0	$ 0

Loans and Allowance for Loan _3

Loans and Allowance for Loan Losses - Schedule of Accounts, Notes, Loans and Financing Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans Receivable	$ 4,296,804	$ 4,153,982
Loans Receivable weighted average interest rate	4.29%	4.97%
SEC Schedule, 12-09, Allowance, Credit Loss
Loans Receivable	$ (55,743)	$ (40,294)
Undisbursed portion of loans in process
Loans Receivable	(863,722)	(850,666)
Deferred loan fees and gains, net
Loans Receivable	(9,260)	(7,104)
Commercial construction
Loans Receivable	1,212,837	1,322,861
Commercial Real Estate
Loans Receivable	1,553,677	1,494,172
Industrial revenue bonds
Loans Receivable	14,003	13,189
Consumer auto
Loans Receivable	86,173	151,854
Home Equity Line of Credit
Loans Receivable	114,689	118,988
Loans Receivable, Gross
Loans Receivable	5,225,529	5,052,046
Land development
Loans Receivable	54,010	40,431
One- to four-family residential construction
Loans Receivable	42,793	33,963
Subdivision construction
Loans Receivable	30,894	16,088
Owner occupied one- to four-family residential
Loans Receivable	470,436	387,016
Non-owner occupied one- to four-family residential
Loans Receivable	114,569	120,343
Other residential
Loans Receivable	1,021,145	866,006
Commercial business
Loans Receivable	370,898	313,209
Consumer other
Loans Receivable	40,762	46,720
Acquired Loans Net of Discount
Loans Receivable	$ 98,643	$ 127,206

Loans and Allowance for Loan _4

Loans and Allowance for Loan Losses - Schedule of Loans Classified by Aging Analysis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Commercial construction
Financing Receivables, By Class	$ 0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Commercial Real Estate
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Industrial revenue bonds
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Consumer auto
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Home Equity Line of Credit
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Land development
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | One- to four-family residential construction
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Subdivision construction
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Owner occupied one- to four-family residential
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Other residential
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Commercial business
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Consumer other
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Acquired Loans Net of Discount
Financing Receivables, By Class	0
Financing Receivables Greater Than 90 Days Past Due and Still Accruing | Less Acquired Loans Net of Discount
Financing Receivables, By Class	0
Loans Receivable, Gross
Financing Receivables, By Class	0
Loans Receivable
Financing Receivables, By Class	0
Financial Asset, 30 to 59 Days Past Due | Commercial construction
Financing Receivables, By Class	0	$ 15,085
Financial Asset, 30 to 59 Days Past Due | Commercial Real Estate
Financing Receivables, By Class	0	549
Financial Asset, 30 to 59 Days Past Due | Industrial revenue bonds
Financing Receivables, By Class	0
Financial Asset, 30 to 59 Days Past Due | Consumer auto
Financing Receivables, By Class	364	1,101
Financial Asset, 30 to 59 Days Past Due | Home Equity Line of Credit
Financing Receivables, By Class	153	296
Financial Asset, 30 to 59 Days Past Due | Land development
Financing Receivables, By Class	20
Financial Asset, 30 to 59 Days Past Due | One- to four-family residential construction
Financing Receivables, By Class	1,365
Financial Asset, 30 to 59 Days Past Due | Subdivision construction
Financing Receivables, By Class	0
Financial Asset, 30 to 59 Days Past Due | Owner occupied one- to four-family residential
Financing Receivables, By Class	1,379	1,453
Financial Asset, 30 to 59 Days Past Due | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	0	152
Financial Asset, 30 to 59 Days Past Due | Other residential
Financing Receivables, By Class	0	376
Financial Asset, 30 to 59 Days Past Due | Commercial business
Financing Receivables, By Class	0	60
Financial Asset, 30 to 59 Days Past Due | Consumer other
Financing Receivables, By Class	443	278
Financial Asset, 30 to 59 Days Past Due | Acquired Loans Net of Discount
Financing Receivables, By Class	1,662	2,177
Financial Asset, 30 to 59 Days Past Due | Less Acquired Loans Net of Discount
Financing Receivables, By Class	1,662	2,177
Financial Asset, 30 to 59 Days Past Due | Loans Receivable, Gross
Financing Receivables, By Class	5,386	21,527
Financial Asset, 30 to 59 Days Past Due | Loans Receivable
Financing Receivables, By Class	3,724	19,350
Financial Asset, 60 to 89 Days Past Due | Commercial construction
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Commercial Real Estate
Financing Receivables, By Class	79	119
Financial Asset, 60 to 89 Days Past Due | Industrial revenue bonds
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Consumer auto
Financing Receivables, By Class	119	259
Financial Asset, 60 to 89 Days Past Due | Home Equity Line of Credit
Financing Receivables, By Class	111
Financial Asset, 60 to 89 Days Past Due | Land development
Financing Receivables, By Class	0	27
Financial Asset, 60 to 89 Days Past Due | One- to four-family residential construction
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Subdivision construction
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Owner occupied one- to four-family residential
Financing Receivables, By Class	113	1,631
Financial Asset, 60 to 89 Days Past Due | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Other residential
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Commercial business
Financing Receivables, By Class	0
Financial Asset, 60 to 89 Days Past Due | Consumer other
Financing Receivables, By Class	7	233
Financial Asset, 60 to 89 Days Past Due | Acquired Loans Net of Discount
Financing Receivables, By Class	641	709
Financial Asset, 60 to 89 Days Past Due | Less Acquired Loans Net of Discount
Financing Receivables, By Class	641	709
Financial Asset, 60 to 89 Days Past Due | Loans Receivable, Gross
Financing Receivables, By Class	1,070	2,978
Financial Asset, 60 to 89 Days Past Due | Loans Receivable
Financing Receivables, By Class	429	2,269
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial construction
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial Real Estate
Financing Receivables, By Class	587	632
Financial Asset, Equal to or Greater than 90 Days Past Due | Industrial revenue bonds
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Consumer auto
Financing Receivables, By Class	169	558
Financial Asset, Equal to or Greater than 90 Days Past Due | Home Equity Line of Credit
Financing Receivables, By Class	508	517
Financial Asset, Equal to or Greater than 90 Days Past Due | Land development
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | One- to four-family residential construction
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Subdivision construction
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Owner occupied one- to four-family residential
Financing Receivables, By Class	1,502	1,198
Financial Asset, Equal to or Greater than 90 Days Past Due | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	69	181
Financial Asset, Equal to or Greater than 90 Days Past Due | Other residential
Financing Receivables, By Class	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial business
Financing Receivables, By Class	114	1,235
Financial Asset, Equal to or Greater than 90 Days Past Due | Consumer other
Financing Receivables, By Class	94	198
Financial Asset, Equal to or Greater than 90 Days Past Due | Acquired Loans Net of Discount
Financing Receivables, By Class	3,843	6,191
Financial Asset, Equal to or Greater than 90 Days Past Due | Less Acquired Loans Net of Discount
Financing Receivables, By Class	3,843	6,191
Financial Asset, Equal to or Greater than 90 Days Past Due | Loans Receivable, Gross
Financing Receivables, By Class	6,886	10,710
Financial Asset, Equal to or Greater than 90 Days Past Due | Loans Receivable
Financing Receivables, By Class	3,043	4,519
Financing Receivables Past Due | Commercial construction
Financing Receivables, By Class	0	15,085
Financing Receivables Past Due | Commercial Real Estate
Financing Receivables, By Class	666	1,300
Financing Receivables Past Due | Industrial revenue bonds
Financing Receivables, By Class	0
Financing Receivables Past Due | Consumer auto
Financing Receivables, By Class	652	1,918
Financing Receivables Past Due | Home Equity Line of Credit
Financing Receivables, By Class	772	813
Financing Receivables Past Due | Land development
Financing Receivables, By Class	20	27
Financing Receivables Past Due | One- to four-family residential construction
Financing Receivables, By Class	1,365
Financing Receivables Past Due | Subdivision construction
Financing Receivables, By Class	0
Financing Receivables Past Due | Owner occupied one- to four-family residential
Financing Receivables, By Class	2,994	4,282
Financing Receivables Past Due | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	69	333
Financing Receivables Past Due | Other residential
Financing Receivables, By Class	0	376
Financing Receivables Past Due | Commercial business
Financing Receivables, By Class	114	1,295
Financing Receivables Past Due | Consumer other
Financing Receivables, By Class	544	709
Financing Receivables Past Due | Acquired Loans Net of Discount
Financing Receivables, By Class	6,146	9,077
Financing Receivables Past Due | Less Acquired Loans Net of Discount
Financing Receivables, By Class	6,146	9,077
Financing Receivables Past Due | Loans Receivable, Gross
Financing Receivables, By Class	13,342	35,215
Financing Receivables Past Due | Loans Receivable
Financing Receivables, By Class	7,196	26,138
Financing Receivables Current | Commercial construction
Financing Receivables, By Class	1,212,837	1,307,776
Financing Receivables Current | Commercial Real Estate
Financing Receivables, By Class	1,553,011	1,492,872
Financing Receivables Current | Industrial revenue bonds
Financing Receivables, By Class	14,003	13,189
Financing Receivables Current | Consumer auto
Financing Receivables, By Class	85,521	149,936
Financing Receivables Current | Home Equity Line of Credit
Financing Receivables, By Class	113,917	118,175
Financing Receivables Current | Land development
Financing Receivables, By Class	53,990	40,404
Financing Receivables Current | One- to four-family residential construction
Financing Receivables, By Class	41,428	33,963
Financing Receivables Current | Subdivision construction
Financing Receivables, By Class	30,894	16,088
Financing Receivables Current | Owner occupied one- to four-family residential
Financing Receivables, By Class	467,442	382,734
Financing Receivables Current | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	114,500	120,010
Financing Receivables Current | Other residential
Financing Receivables, By Class	1,021,145	865,630
Financing Receivables Current | Commercial business
Financing Receivables, By Class	370,784	311,914
Financing Receivables Current | Consumer other
Financing Receivables, By Class	40,218	46,011
Financing Receivables Current | Acquired Loans Net of Discount
Financing Receivables, By Class	92,497	118,129
Financing Receivables Current | Less Acquired Loans Net of Discount
Financing Receivables, By Class	92,497	118,129
Financing Receivables Current | Loans Receivable, Gross
Financing Receivables, By Class	5,212,187	5,016,831
Financing Receivables Current | Loans Receivable
Financing Receivables, By Class	5,119,690	4,898,702
Financing Receivables Total | Commercial construction
Financing Receivables, By Class	1,212,837	1,322,861
Financing Receivables Total | Commercial Real Estate
Financing Receivables, By Class	1,553,677	1,494,172
Financing Receivables Total | Industrial revenue bonds
Financing Receivables, By Class	14,003	13,189
Financing Receivables Total | Consumer auto
Financing Receivables, By Class	86,173	151,854
Financing Receivables Total | Home Equity Line of Credit
Financing Receivables, By Class	114,689	118,988
Financing Receivables Total | Land development
Financing Receivables, By Class	54,010	40,431
Financing Receivables Total | One- to four-family residential construction
Financing Receivables, By Class	42,793	33,963
Financing Receivables Total | Subdivision construction
Financing Receivables, By Class	30,894	16,088
Financing Receivables Total | Owner occupied one- to four-family residential
Financing Receivables, By Class	470,436	387,016
Financing Receivables Total | Non-owner occupied one- to four-family residential
Financing Receivables, By Class	114,569	120,343
Financing Receivables Total | Other residential
Financing Receivables, By Class	1,021,145	866,006
Financing Receivables Total | Commercial business
Financing Receivables, By Class	370,898	313,209
Financing Receivables Total | Consumer other
Financing Receivables, By Class	40,762	46,720
Financing Receivables Total | Acquired Loans Net of Discount
Financing Receivables, By Class	98,643	127,206
Financing Receivables Total | Less Acquired Loans Net of Discount
Financing Receivables, By Class	98,643	127,206
Financing Receivables Total | Loans Receivable, Gross
Financing Receivables, By Class	5,225,529	5,052,046
Financing Receivables Total | Loans Receivable
Financing Receivables, By Class	$ 5,126,886	$ 4,924,840

Loans and Allowance for Loan _5

Loans and Allowance for Loan Losses - Financing Receivable, Nonaccrual (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans Receivable
Financing Receivable, Nonaccrual	$ 3,043	$ 4,519
Commercial Real Estate
Financing Receivable, Nonaccrual	587	632
Consumer auto
Financing Receivable, Nonaccrual	169	558
Home Equity Line of Credit
Financing Receivable, Nonaccrual	508	517
Owner occupied one- to four-family residential
Financing Receivable, Nonaccrual	1,502	1,198
Non-owner occupied one- to four-family residential
Financing Receivable, Nonaccrual	69	181
Commercial business
Financing Receivable, Nonaccrual	114	1,235
Consumer other
Financing Receivable, Nonaccrual	$ 94	$ 198

Loans and Allowance for Loan _6

Loans and Allowance for Loan Losses - Financing Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Provision for Loan and Lease Losses	$ 15,871	$ 6,150	$ 7,150
Loans Receivable
Provision for Loan and Lease Losses	55,743	40,294	38,409	$ 36,492
Financing Receivable, Credit Loss, Expense (Reversal)	15,871	6,150	7,150
Financing Receivable, Allowance for Credit Loss, Writeoff	(3,294)	(8,062)	(11,356)
Accounts Receivable, Allowance for Credit Loss, Recovery	2,872	3,797	6,123
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	713	929	2,041
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	54,350	38,704	35,947
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	680	661	421
Financing Receivable, Individually Evaluated for Impairment	9,048	10,267	13,939
Financing Receivable, Collectively Evaluated for Impairment	5,117,838	4,914,573	4,811,661
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	98,643	127,206	167,651
Individually evaluated for impairment	713	929	2,041
Collectively evaluated for impairment	54,350	38,704	35,947
Individually evaluated for impairment	9,048	10,267	13,939
Collectively evaluated for impairment	5,117,838	4,914,573	4,811,661
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	98,643	127,206	167,651
Commercial Real Estate
Provision for Loan and Lease Losses	33,707	24,334	19,803	18,639
Financing Receivable, Credit Loss, Expense (Reversal)	9,343	4,651	1,094
Financing Receivable, Allowance for Credit Loss, Writeoff	(43)	(144)	(102)
Accounts Receivable, Allowance for Credit Loss, Recovery	73	24	172
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	445	517	613
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	32,937	23,570	18,958
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	325	247	232
Financing Receivable, Individually Evaluated for Impairment	3,438	4,020	3,501
Financing Receivable, Collectively Evaluated for Impairment	1,550,239	1,490,152	1,367,934
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	24,613	29,158	33,620
Individually evaluated for impairment	445	517	613
Collectively evaluated for impairment	32,937	23,570	18,958
Individually evaluated for impairment	3,438	4,020	3,501
Collectively evaluated for impairment	1,550,239	1,490,152	1,367,934
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	24,613	29,158	33,620
Commercial construction
Provision for Loan and Lease Losses	3,521	3,076	3,105	1,767
Financing Receivable, Credit Loss, Expense (Reversal)	242	22	1,031
Financing Receivable, Allowance for Credit Loss, Writeoff	(1)	(101)	(87)
Accounts Receivable, Allowance for Credit Loss, Recovery	204	50	394
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	3,378	2,940	3,029
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	143	136	76
Financing Receivable, Individually Evaluated for Impairment			14
Financing Receivable, Collectively Evaluated for Impairment	1,266,847	1,363,292	1,461,644
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	2,551	3,606	4,093
Collectively evaluated for impairment	3,378	2,940	3,029
Individually evaluated for impairment			14
Collectively evaluated for impairment	1,266,847	1,363,292	1,461,644
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	2,551	3,606	4,093
One- to four-family residential construction
Provision for Loan and Lease Losses	4,536	4,339	3,122	2,108
Financing Receivable, Credit Loss, Expense (Reversal)	84	1,625	742
Financing Receivable, Allowance for Credit Loss, Writeoff	(70)	(534)	(62)
Accounts Receivable, Allowance for Credit Loss, Recovery	183	126	334
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	90	198	694
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	4,382	3,973	2,392
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	64	168	36
Financing Receivable, Individually Evaluated for Impairment	3,546	2,960	6,116
Financing Receivable, Collectively Evaluated for Impairment	655,146	554,450	433,209
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	57,113	74,562	93,841
Individually evaluated for impairment	90	198	694
Collectively evaluated for impairment	4,382	3,973	2,392
Individually evaluated for impairment	3,546	2,960	6,116
Collectively evaluated for impairment	655,146	554,450	433,209
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	57,113	74,562	93,841
Other residential
Provision for Loan and Lease Losses	9,375	5,153	4,713	2,839
Financing Receivable, Credit Loss, Expense (Reversal)	4,042	603	1,982
Financing Receivable, Allowance for Credit Loss, Writeoff		(189)	(525)
Accounts Receivable, Allowance for Credit Loss, Recovery	180	26	417
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	9,282	5,101	4,681
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	93	52	32
Financing Receivable, Collectively Evaluated for Impairment	1,021,145	866,006	784,894
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	6,150	5,334	12,790
Collectively evaluated for impairment	9,282	5,101	4,681
Collectively evaluated for impairment	1,021,145	866,006	784,894
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	6,150	5,334	12,790
Commercial business
Provision for Loan and Lease Losses	2,390	1,355	1,568	3,581
Financing Receivable, Credit Loss, Expense (Reversal)	914	(309)	(1,613)
Financing Receivable, Allowance for Credit Loss, Writeoff	(28)	(371)	(1,155)
Accounts Receivable, Allowance for Credit Loss, Recovery	149	467	755
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	14	13	309
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,331	1,306	1,247
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	45	36	12
Financing Receivable, Individually Evaluated for Impairment	167	1,286	1,844
Financing Receivable, Collectively Evaluated for Impairment	384,734	325,112	334,214
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	2,549	3,356	4,347
Individually evaluated for impairment	14	13	309
Collectively evaluated for impairment	2,331	1,306	1,247
Individually evaluated for impairment	167	1,286	1,844
Collectively evaluated for impairment	384,734	325,112	334,214
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	2,549	3,356	4,347
Consumer other
Provision for Loan and Lease Losses	2,214	2,037	6,098	$ 7,558
Financing Receivable, Credit Loss, Expense (Reversal)	1,246	(442)	3,914
Financing Receivable, Allowance for Credit Loss, Writeoff	(3,152)	(6,723)	(9,425)
Accounts Receivable, Allowance for Credit Loss, Recovery	2,083	3,104	4,051
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	164	201	425
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,040	1,814	5,640
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	10	22	33
Financing Receivable, Individually Evaluated for Impairment	1,897	2,001	2,464
Financing Receivable, Collectively Evaluated for Impairment	239,727	315,561	429,766
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	5,667	11,190	18,960
Individually evaluated for impairment	164	201	425
Collectively evaluated for impairment	2,040	1,814	5,640
Individually evaluated for impairment	1,897	2,001	2,464
Collectively evaluated for impairment	239,727	315,561	429,766
All Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Not Accounted for Using Income Recognition Model	$ 5,667	$ 11,190	$ 18,960

Loans and Allowance for Loan _7

Loans and Allowance for Loan Losses - Weighted Average Interest Rate on Loans Receivable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Loans Receivable, Weighted Average Interest Rate	4.29%	4.97%
Commercial loan participations sold to other financial institutions	$ 308.4	$ 283
Residential mortgage loans sold	154.3	66.9
Unpaid principal balances
Loans serviced for others	462.7	349.9
Unused lines of Credit
Loans serviced for others	$ 46.1	$ 102.1

Loans and Allowance for Loan _8

Loans and Allowance for Loan Losses - Impaired Financing Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans Receivable
Impaired Financing Receivable, Recorded Investment	$ 9,048	$ 10,267	$ 13,939
Impaired Financing Receivable, Unpaid Principal Balance	10,109	11,435	15,579
Impaired Financing Receivable, Related Allowance	713	929	2,041
Impaired Financing Receivable, Average Recorded Investment	9,739	12,487	20,004
Impaired Financing Receivable Interest Income Recognized	533	839	1,346
Commercial construction
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Commercial Real Estate
Impaired Financing Receivable, Recorded Investment	3,438	4,020	3,501
Impaired Financing Receivable, Unpaid Principal Balance	3,472	4,049	3,665
Impaired Financing Receivable, Related Allowance	445	517	613
Impaired Financing Receivable, Average Recorded Investment	3,736	4,940	6,216
Impaired Financing Receivable Interest Income Recognized	135	264	337
Industrial revenue bonds
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Consumer auto
Impaired Financing Receivable, Recorded Investment	865	1,117	1,874
Impaired Financing Receivable, Unpaid Principal Balance	964	1,334	2,114
Impaired Financing Receivable, Related Allowance	140	181	336
Impaired Financing Receivable, Average Recorded Investment	932	1,128	2,069
Impaired Financing Receivable Interest Income Recognized	91	125	167
Home Equity Line of Credit
Impaired Financing Receivable, Recorded Investment	630	528	111
Impaired Financing Receivable, Unpaid Principal Balance	668	548	128
Impaired Financing Receivable, Related Allowance	5	4	17
Impaired Financing Receivable, Average Recorded Investment	550	362	412
Impaired Financing Receivable Interest Income Recognized	36	37	28
Land development
Impaired Financing Receivable, Recorded Investment	0	0	14
Impaired Financing Receivable, Unpaid Principal Balance	0	0	18
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	328	14
Impaired Financing Receivable Interest Income Recognized	0	101	1
One- to four-family residential construction
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Subdivision construction
Impaired Financing Receivable, Recorded Investment	20	251	318
Impaired Financing Receivable, Unpaid Principal Balance	20	251	318
Impaired Financing Receivable, Related Allowance	0	96	105
Impaired Financing Receivable, Average Recorded Investment	115	277	321
Impaired Financing Receivable Interest Income Recognized	3	9	17
Owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	3,457	2,300	3,576
Impaired Financing Receivable, Unpaid Principal Balance	3,776	2,423	3,926
Impaired Financing Receivable, Related Allowance	90	82	285
Impaired Financing Receivable, Average Recorded Investment	2,999	2,598	3,406
Impaired Financing Receivable Interest Income Recognized	169	131	197
Non-owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	69	409	2,222
Impaired Financing Receivable, Unpaid Principal Balance	106	574	2,519
Impaired Financing Receivable, Related Allowance	0	20	304
Impaired Financing Receivable, Average Recorded Investment	309	954	2,870
Impaired Financing Receivable Interest Income Recognized	18	43	158
Other residential
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	1,026
Impaired Financing Receivable Interest Income Recognized	0	0	20
Commercial business
Impaired Financing Receivable, Recorded Investment	166	1,286	1,844
Impaired Financing Receivable, Unpaid Principal Balance	551	1,771	2,207
Impaired Financing Receivable, Related Allowance	14	13	309
Impaired Financing Receivable, Average Recorded Investment	800	1,517	2,932
Impaired Financing Receivable Interest Income Recognized	34	81	362
Consumer other
Impaired Financing Receivable, Recorded Investment	403	356	479
Impaired Financing Receivable, Unpaid Principal Balance	552	485	684
Impaired Financing Receivable, Related Allowance	19	16	72
Impaired Financing Receivable, Average Recorded Investment	298	383	738
Impaired Financing Receivable Interest Income Recognized	$ 47	$ 48	$ 59

Loans and Allowance for Loan _9

Loans and Allowance for Loan Losses - Impaired Loans Specific Valuation Allowance (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans and Allowance for Loan Losses
Impaired Loans With Specific Valuation Allowance	$ 4,800,000	$ 5,200,000	$ 8,400,000
Impaired Loans Valuation Allowance	713,000	929,000	2,000,000
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 579,000	$ 761,000	$ 1,000,000

Loans and Allowance for Loan_10

Loans and Allowance for Loan Losses - Financing Receivable, Troubled Debt Restructuring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Construction and land development
Troubled Debt Restructuring Loans Modified Term			$ 31
Troubled Debt Restructurings Total New Modifications			31
Commercial business
Troubled Debt Restructuring Loans Modified Combination	$ 22
Troubled Debt Restructurings Total New Modifications	22
Consumer other
Troubled Debt Restructuring Loans Modified Term	16	$ 136	535
Troubled Debt Restructuring Loans Modified Combination	1,951
Troubled Debt Restructurings Total New Modifications	1,967	136	535
Newly Restructured Modified Loans
Troubled Debt Restructuring Loans Interest Only			1,348
Troubled Debt Restructuring Loans Modified Term	16	136	566
Troubled Debt Restructuring Loans Modified Combination	3,562		106
Troubled Debt Restructurings Total New Modifications	3,578	$ 136	2,020
Commercial Real Estate
Troubled Debt Restructuring Loans Modified Combination	559
Troubled Debt Restructurings Total New Modifications	559
Commercial construction
Troubled Debt Restructuring Loans Modified Combination			106
Troubled Debt Restructurings Total New Modifications			106
One- to four-family residential
Troubled Debt Restructuring Loans Interest Only			1,348
Troubled Debt Restructuring Loans Modified Combination	1,030
Troubled Debt Restructurings Total New Modifications	$ 1,030		$ 1,348

Loans and Allowance for Loan_11

Loans and Allowance for Loan Losses - Loans Modified in Troubled Debt Restructurings by Segment (Details)	12 Months Ended
	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)
Troubled Debt Restructurings Total Modifications	$ 3,300,000	$ 1,900,000
Troubled Debt Restructurings Accruing Interest	$ 2,400,000	1,400,000
Troubled Debt Restructurings		562,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | item	0
Substandard
Troubled Debt Restructurings	$ 1,600,000
Commercial Real Estate
Troubled Debt Restructured Loans and Impaired	646,000	412,000
Consumer Loan
Troubled Debt Restructured Loans and Impaired	629,000	343,000
Construction and land development
Troubled Debt Restructured Loans and Impaired	20,000	251,000
Commercial business
Troubled Debt Restructured Loans and Impaired	127,000	156,000
Single Family Residential Mortgage
Troubled Debt Restructured Loans and Impaired	$ 1,900,000	$ 768,000

Loans and Allowance for Loan_12

Loans and Allowance for Loan Losses - Troubled Debt Restructured Loans Returned to Accrual Status (Details)	12 Months Ended
	Dec. 31, 2019USD ($)
One- to four-family residential
Troubled Debt Restructurings Returned to Accrual Status	$ 372,000

Loans and Allowance for Loan_13

Loans and Allowance for Loan Losses - CARES Act (Details) $ in Millions	Dec. 31, 2020USD ($)
Commercial Lending Customer
Number of CARES Act Loan Modifications	65
CARES Act Loan Modifications	$ 233
Consumer and Mortgage Loans
Number of CARES Act Loan Modifications	581
CARES Act Loan Modifications	$ 18

Loans and Allowance for Loan_14

Loans and Allowance for Loan Losses - Financing Receivable Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans Receivable
Loan Portfolio Internal Grading System Classification	$ 5,225,529	$ 5,052,046
Commercial construction
Loan Portfolio Internal Grading System Classification	1,212,837	1,322,861
Commercial Real Estate
Loan Portfolio Internal Grading System Classification	1,553,677	1,494,172
Industrial revenue bonds
Loan Portfolio Internal Grading System Classification	14,003	13,189
Consumer auto
Loan Portfolio Internal Grading System Classification	86,173	151,854
Home Equity Line of Credit
Loan Portfolio Internal Grading System Classification	114,689	118,988
Land development
Loan Portfolio Internal Grading System Classification	54,010	40,431
One- to four-family residential construction
Loan Portfolio Internal Grading System Classification	42,793	33,963
Subdivision construction
Loan Portfolio Internal Grading System Classification	30,894	16,088
Owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	470,436	387,016
Non-owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	114,569	120,343
Other residential
Loan Portfolio Internal Grading System Classification	1,021,145	866,006
Commercial business
Loan Portfolio Internal Grading System Classification	370,898	313,209
Consumer other
Loan Portfolio Internal Grading System Classification	40,762	46,720
Acquired Loans Net of Discount
Loan Portfolio Internal Grading System Classification	98,643	127,206
Satisfactory | Loans Receivable
Loan Portfolio Internal Grading System Classification	5,153,396	5,005,765
Satisfactory | Commercial construction
Loan Portfolio Internal Grading System Classification	1,212,837	1,322,861
Satisfactory | Commercial Real Estate
Loan Portfolio Internal Grading System Classification	1,498,031	1,458,400
Satisfactory | Industrial revenue bonds
Loan Portfolio Internal Grading System Classification	14,003	13,189
Satisfactory | Consumer auto
Loan Portfolio Internal Grading System Classification	85,657	150,874
Satisfactory | Home Equity Line of Credit
Loan Portfolio Internal Grading System Classification	114,049	118,428
Satisfactory | Land development
Loan Portfolio Internal Grading System Classification	54,010	40,431
Satisfactory | One- to four-family residential construction
Loan Portfolio Internal Grading System Classification	41,428	33,963
Satisfactory | Subdivision construction
Loan Portfolio Internal Grading System Classification	30,874	16,061
Satisfactory | Owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	467,855	385,001
Satisfactory | Non-owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	114,176	119,743
Satisfactory | Other residential
Loan Portfolio Internal Grading System Classification	1,017,648	866,006
Satisfactory | Commercial business
Loan Portfolio Internal Grading System Classification	363,681	307,322
Satisfactory | Consumer other
Loan Portfolio Internal Grading System Classification	40,514	46,294
Satisfactory | Acquired Loans Net of Discount
Loan Portfolio Internal Grading System Classification	98,633	127,192
Watch | Loans Receivable
Loan Portfolio Internal Grading System Classification	64,758	37,368
Watch | Commercial Real Estate
Loan Portfolio Internal Grading System Classification	52,208	32,063
Watch | Consumer auto
Loan Portfolio Internal Grading System Classification	5	47
Watch | Home Equity Line of Credit
Loan Portfolio Internal Grading System Classification	39	43
Watch | One- to four-family residential construction
Loan Portfolio Internal Grading System Classification	1,365
Watch | Subdivision construction
Loan Portfolio Internal Grading System Classification		27
Watch | Owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	216	26
Watch | Non-owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	324	419
Watch | Other residential
Loan Portfolio Internal Grading System Classification	3,497
Watch | Commercial business
Loan Portfolio Internal Grading System Classification	7,102	4,651
Watch | Consumer other
Loan Portfolio Internal Grading System Classification	2	92
Substandard | Loans Receivable
Loan Portfolio Internal Grading System Classification	7,375	8,913
Substandard | Commercial Real Estate
Loan Portfolio Internal Grading System Classification	3,438	3,709
Substandard | Consumer auto
Loan Portfolio Internal Grading System Classification	511	933
Substandard | Home Equity Line of Credit
Loan Portfolio Internal Grading System Classification	601	517
Substandard | Subdivision construction
Loan Portfolio Internal Grading System Classification	20
Substandard | Owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	2,365	1,989
Substandard | Non-owner occupied one- to four-family residential
Loan Portfolio Internal Grading System Classification	69	181
Substandard | Commercial business
Loan Portfolio Internal Grading System Classification	115	1,236
Substandard | Consumer other
Loan Portfolio Internal Grading System Classification	246	334
Substandard | Acquired Loans Net of Discount
Loan Portfolio Internal Grading System Classification	$ 10	$ 14

Loans and Allowance for Loan_15

Loans and Allowance for Loan Losses - Schedule of related party transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Loans and Allowance for Loan Losses
Balance, beginning of year	$ 15,240	$ 29,017
New loans	901	15,062
Payments	(2,673)	(28,839)
Balance, end of year	$ 13,468	$ 15,240

FDIC-Acquired Loans and Loss _3

FDIC-Acquired Loans and Loss Sharing Agreements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jun. 09, 2017	Apr. 26, 2016	Jun. 20, 2014
Business Acquisition [Line Items]
Goodwill recorded on acquisition date	$ 6,944,000	$ 8,098,000
TeamBank
Business Acquisition [Line Items]
Gross loans receivable	5,393,000	7,304,000
Balance of accretable discount due to change in expected losses	(97,000)	(159,000)
Net carrying value of loans receivable	(5,266,000)	(7,118,000)
Expected loss remaining	30,000	27,000
Goodwill recorded on acquisition date				$ 0
Vantus Bank
Business Acquisition [Line Items]
Gross loans receivable	8,052,000	9,899,000
Balance of accretable discount due to change in expected losses	(35,000)	(89,000)
Net carrying value of loans receivable	(8,004,000)	(9,797,000)
Expected loss remaining	13,000	13,000
Goodwill recorded on acquisition date				0
Sun Security Bank
Business Acquisition [Line Items]
Gross loans receivable	13,395,000	17,906,000
Balance of accretable discount due to change in expected losses	(180,000)	(374,000)
Net carrying value of loans receivable	(13,111,000)	(17,392,000)
Expected loss remaining	104,000	140,000
Goodwill recorded on acquisition date				$ 0
InterBank
Business Acquisition [Line Items]
Gross loans receivable	44,215,000	60,430,000
Balance of accretable discount due to change in expected losses	(1,079,000)	(5,143,000)
Net carrying value of loans receivable	(42,057,000)	(54,442,000)
Expected loss remaining	1,079,000	845,000
Goodwill recorded on acquisition date			$ 0
Valley Bank
Business Acquisition [Line Items]
Gross loans receivable	31,515,000	41,032,000
Balance of accretable discount due to change in expected losses	(612,000)	(1,803,000)
Net carrying value of loans receivable	(30,204,000)	(38,452,000)
Expected loss remaining	$ 699,000	$ 777,000
Goodwill recorded on acquisition date					$ 0

FDIC-Acquired Loans and Loss _4

FDIC-Acquired Loans and Loss Sharing Agreements - Fair Value and Expected Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
FDIC-Acquired Loans and Loss Sharing Agreements
Increase in accretable yield due to increased cash flow expectations	$ 12,323	$ 5,202

FDIC-Acquired Loans and Loss _5

FDIC-Acquired Loans and Loss Sharing Agreements - Consolidated Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
FDIC-Acquired Loans and Loss Sharing Agreements
Interest income and net impact to pre-tax income	$ 5,574	$ 7,431	$ 5,134
Remaining accretable yield adjustment	2,000
Expected interest income	$ 1,500

FDIC-Acquired Loans and Loss _6

FDIC-Acquired Loans and Loss Sharing Agreements - Accretable Yield Changes for Acquired Loans (Details) - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
TeamBank
Business Acquisition [Line Items]
Beginning Balance		$ 1,157,000	$ 1,356,000	$ 2,071,000
Accretion		(479,000)	(955,000)	(1,042,000)
Reclassification from nonaccretable difference	[1]	198,000	756,000	327,000
Ending balance		876,000	1,157,000	1,356,000
Change in expected accretable yield		198,000	667,000	312,000
Vantus Bank
Business Acquisition [Line Items]
Beginning Balance		1,123,000	1,432,000	1,850,000
Accretion		(831,000)	(1,006,000)	(1,196,000)
Reclassification from nonaccretable difference	[1]	451,000	697,000	778,000
Ending balance		743,000	1,123,000	1,432,000
Change in expected accretable yield		451,000	480,000	778,000
Sun Security Bank
Business Acquisition [Line Items]
Beginning Balance		1,948,000	2,242,000	2,901,000
Accretion		(1,046,000)	(1,562,000)	(1,667,000)
Reclassification from nonaccretable difference	[1]	493,000	1,268,000	1,008,000
Ending balance		1,395,000	1,948,000	2,242,000
Change in expected accretable yield		493,000	810,000	756,000
InterBank
Business Acquisition [Line Items]
Beginning Balance		8,277,000	4,994,000	5,074,000
Accretion		(6,791,000)	(8,798,000)	(8,349,000)
Reclassification from nonaccretable difference	[1]	2,219,000	12,081,000	8,269,000
Ending balance		3,705,000	8,277,000	4,994,000
Change in expected accretable yield		2,200,000	3,900,000	4,100,000
Valley Bank
Business Acquisition [Line Items]
Beginning Balance		4,578,000	3,063,000	2,695,000
Accretion		(3,005,000)	(4,302,000)	(3,892,000)
Reclassification from nonaccretable difference	[1]	2,764,000	5,817,000	4,260,000
Ending balance		4,337,000	4,578,000	3,063,000
Change in expected accretable yield		$ 2,800,000	$ 2,500,000	$ 3,500,000
[1]	Represents increases in estimated cash flows expected to be received from the acquired loan pools, primarily due to lower estimated credit losses. The numbers also include changes in expected accretion of the loan pools for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2020, totaling $198,000, $451,000, $493,000, $2.2 million and $2.8 million, respectively; TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2019, totaling $667,000, $480,000, $810,000, $3.9 million and $2.5 million, respectively; for TeamBank, Vantus Bank, Sun Security Bank, InterBank and Valley Bank for the year ended December 31, 2018, totaling $312,000, $778,000, $756,000, $4.1 million and $3.5 million, respectively

Other Real Estate Owned and R_3

Other Real Estate Owned and Repossessions - Schedule of Major Classifications of Foreclosed Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Foreclosed Assets Held for Sale and Repossessions	$ 777	$ 3,651
Foreclosed assets held for sale and repossessions, net	1,223	4,654
Other real estate owned not acquired through foreclosure	654	871
Other real estate owned and repossessions	1,877	5,525
Foreclosed Assets Held For Sale And Repossessions Net [Member] | Valley Bank
Foreclosed assets related to FDIC acquisitions, net of discounts	446	1,003
One- to four-family residential
Foreclosed Assets Held for Sale and Repossessions	111	601
Commercial Real Estate
Foreclosed Assets Held for Sale and Repossessions	0	0
Land development
Foreclosed Assets Held for Sale and Repossessions	250	1,816
One- to four-family residential construction
Foreclosed Assets Held for Sale and Repossessions	0	0
Subdivision construction
Foreclosed Assets Held for Sale and Repossessions	263	689
Other residential
Foreclosed Assets Held for Sale and Repossessions	0	0
Commercial business
Foreclosed Assets Held for Sale and Repossessions	0	0
Consumer other
Foreclosed Assets Held for Sale and Repossessions	$ 153	$ 545

Other Real Estate Owned and R_4

Other Real Estate Owned and Repossessions - Schedule of Expenses Applicable to Foreclosed Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Real Estate Owned and Repossessions
Net (gain) loss on sales of other real estate owned	$ (480)	$ (750)	$ (2,522)
Valuation write-downs on foreclosed assets	1,320	926	3,897
Operating expenses, net of rental income	1,183	2,008	3,544
Expenses on real estate and repossessions	$ 2,023	$ 2,184	$ 4,919

Other Real Estate Owned and R_5

Other Real Estate Owned and Repossessions (Details)	12 Months Ended
	Dec. 31, 2020USD ($)property	Dec. 31, 2019USD ($)property	Dec. 31, 2018USD ($)
Gain On Sale Of Branch Location		$ 115,000
Number of real estate properties | property	7	6
Foreclosure assets held for sale	$ 1,223,000	$ 4,654,000
Valuation write-downs on foreclosed assets	1,320,000	926,000	$ 3,897,000
Operating leases right of use asset	8,536,000	8,668,000
Lease liability	$ 8,661,000	$ 8,747,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Lease liability	Lease liability
Former branch
Foreclosure assets held for sale	$ 80,000
Valuation write-downs on foreclosed assets	286,000
Residential Mortgage [Member]
Mortgage Loans in Process of Foreclosure, Amount	602,000	$ 1,600,000
Acquired Loans | Residential Mortgage [Member]
Mortgage Loans in Process of Foreclosure, Amount	$ 518,000	$ 1,400,000

Premises and Equipment - Proper

Premises and Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Premises and Equipment
Land	$ 40,652	$ 40,632
Buildings and improvements	100,187	96,959
Operating leases right of use asset	8,536	8,668
Furniture, fixtures and equipment	59,226	56,986
Premises and equipment, gross	208,601	203,245
Less accumulated depreciation	69,431	61,337
Total Premises and Equipment	$ 139,170	$ 141,908

Premises and Equipment - Calcul

Premises and Equipment - Calculated Amount of Right of Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Premises and Equipment
Operating leases right of use asset	$ 8,536	$ 8,668
Operating leases liability	8,661	8,747
Operating lease costs classified as occupancy and equipment expense	1,572	1,460
Operating cash flows from operating leases	1,526	1,381
Operating leases	$ 972	$ 9,538

Premises and Equipment - Future

Premises and Equipment - Future Minimum Rental Payments for Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Premises and Equipment
2020	$ 1,119
2021	1,116
2022	1,088
2023	1,005
2024	979
Thereafter	4,926
Future lease payments expected	10,233
Less:Interest portion of lease payments	(1,572)
Lease liability	$ 8,661	$ 8,747

Premises and Equipment - Additi

Premises and Equipment - Additional information (Details)	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Number Of Lessee Lease Agreements		15
Initial Leases And Lease Modifications And Renewals		$ 9,500,000
Lease expense related to ATMs	$ 275,000	$ 286,000
Weighted-average lease term		P8Y3M18D
Operating Lease, Weighted Average Discount Rate, Percent	3.24%
Operating Lease, Expense	$ 1,600,000	$ 1,500,000
Operating leases right of use asset	8,536,000	8,668,000
Lease liability	8,661,000	8,747,000
Income Recognized From Lessor Agreements	$ 1,200,000	$ 1,100,000
Minimum
Lessee Expected Lease Terms		P0Y9M18D
Maximum
Lessee Expected Lease Terms		P17Y10M24D

Investments in Limited Partne_2

Investments in Limited Partnerships (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary of Investment Holdings [Line Items]
Number of Investments in Affordable Housing Partnerships	16	15
Investments in Affordable Housing Partnerships Carrying Value, Net	$ 20.4	$ 22.8
Federal Affordable Housing Tax Credits	22.1
Expected Amortization of Investments in Affordable Housing Partnerships	20.4
Usage of Federal Affordable Housing Tax Credits	6.6	8	$ 6.6
Actual Amortization of Investments in Affordable Housing Partnerships	$ 5.5	$ 5.8	$ 5
For the First three years
Summary of Investment Holdings [Line Items]
Percentage of investments on credit allowance period	5.00%
For the next four years
Summary of Investment Holdings [Line Items]
Percentage of investments on credit allowance period	6.00%

Investments in Limited Partne_3

Investments in Limited Partnerships - Investments in Community Development Entities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in Limited Partnerships
Investments in Community Development Entities Net Carrying Amount	$ 567,000
Investments In Limited Partnerships For Federal Or Historic Tax Credits	863,000
Usage of Investment in Community Development Entities Federal New Market Tax Credits	100,000	$ 480,000	$ 480,000
Actual Amortization of Investment in Community Development Entities	$ 80,000	$ 365,000	$ 575,000
credit allowance period	7 years
Community Development Entities, Minimum Period Before Redemption	7 years
credit allowance period for federal rehabilitation/historic tax credits	5 years

Investments in Limited Partne_4

Investments in Limited Partnerships - Impaired Loans (Details)	12 Months Ended
	Dec. 31, 2020
Maximum
Summary of Investment Holdings [Line Items]
Discount Rate For Appraisals	40.00%
Minimum
Summary of Investment Holdings [Line Items]
Discount Rate For Appraisals	10.00%

Deposits - Schedule of Deposit

Deposits - Schedule of Deposit Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits	$ 4,516,903	$ 3,960,106
Time deposits	1,390,792	1,721,109
Noninterest-bearing accounts	984,798	687,068
Demand Deposit Accounts	3,126,111	2,238,997
Deposits, domestic	$ 4,516,903	$ 3,960,106
Weighted average interest rate on certificates of deposit	1.00%	2.09%
0.22% and 0.55%
Interest-bearing checking and savings accounts	$ 2,141,313	$ 1,551,929
0.22% and 0.55% | Minimum
Weighted average interest rate on certificates of deposit	0.22%
0.22% and 0.55% | Maximum
Weighted average interest rate on certificates of deposit	0.55%
0.00% - 0.99%
Time deposits	$ 803,737	122,649
0.00% - 0.99% | Minimum
Weighted average interest rate on certificates of deposit	0.00%
0.00% - 0.99% | Maximum
Weighted average interest rate on certificates of deposit	0.99%
1.00% - 1.99%
Time deposits	$ 425,061	523,816
1.00% - 1.99% | Minimum
Weighted average interest rate on certificates of deposit	1.00%
1.00% - 1.99% | Maximum
Weighted average interest rate on certificates of deposit	1.99%
2.00% - 2.99%
Time deposits	$ 143,417	1,053,914
2.00% - 2.99% | Minimum
Weighted average interest rate on certificates of deposit	2.00%
2.00% - 2.99% | Maximum
Weighted average interest rate on certificates of deposit	2.99%
3.00% - 3.99%
Time deposits	$ 18,148	19,849
3.00% - 3.99% | Minimum
Weighted average interest rate on certificates of deposit	3.00%
3.00% - 3.99% | Maximum
Weighted average interest rate on certificates of deposit	3.99%
4% and above
Time deposits	$ 429	$ 881
4% and above | Minimum
Weighted average interest rate on certificates of deposit	4.00%

Deposits - Weighted Average Int

Deposits - Weighted Average Interest Rate on Certificates of Deposit (Details)	Dec. 31, 2020	Dec. 31, 2019
Deposits
Weighted average interest rate on certificates of deposit	1.00%	2.09%

Deposits - Originated Certifica

Deposits - Originated Certificates of Deposit and Brokered Deposits (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deposits
Amount of certificates of deposit greater than $100,000 originated	$ 762.9	$ 830.8
Amount of certificates of deposit greater than $250,000 originated	123.1	153.1
Interest-bearing Domestic Deposit, Brokered	$ 158.7	$ 371.7

Deposits - Maturities of certif

Deposits - Maturities of certificates of deposit (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Time Deposits:
Time Deposits by Category	$ 1,390,792	$ 1,721,109
Certificates of deposit
Time Deposits:
2021	1,087,279
2022	189,664
2023	73,346
2024	25,847
2025	13,743
Thereafter	913
Time Deposits by Category	1,390,792
Retail | Certificates of deposit
Time Deposits:
2021	995,934
2022	175,913
2023	30,898
2024	14,647
2025	13,743
Thereafter	913
Time Deposits by Category	1,232,048
Brokered | Certificates of deposit
Time Deposits:
2021	91,345
2022	13,751
2023	42,448
2024	11,200
Time Deposits by Category	$ 158,744

Deposits - Schedule of Interest

Deposits - Schedule of Interest Expense on Deposit Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deposits
Checking and savings accounts	$ 7,096	$ 7,971	$ 5,982
Certificate accounts	25,453	37,723	22,149
Early withdrawal penalties	(118)	(124)	(174)
Total interest expense on deposits	$ 32,431	$ 45,570	$ 27,957

Advances From Federal Home Lo_2

Advances From Federal Home Loan Bank (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Advances from Federal Home Loan Banks	$ 0	$ 0
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged		1,630,000,000	$ 1,600,000,000
Long-term Line of Credit	0	0
Investment securities specifically pledged as collateral	0	$ 0
Federal Home Loan Bank of Des Moines [Member]
Long-term Line of Credit	$ 1,070,000,000

Short-Term Borrowings (Details)

Short-Term Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Short-Term Borrowings
Notes payable - Community Development Equity Funds	$ 1,518	$ 1,267
Other interest-bearing liabilities		30,890
Overnight borrowings from the Federal Home Loan Bank		196,000
Securities sold under reverse repurchase agreements	164,174	84,167
Short-term borrowings total	$ 165,692	$ 312,324

Short-Term Borrowings - Short-t

Short-Term Borrowings - Short-term borrowings (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Short-Term Borrowings
Weighted average interest rates of short-term borrowings	0.02%	1.25%
Short-term borrowings average	$ 183.5	$ 260
Maximum amounts outstanding of short-term borrowing	$ 318.7	$ 346.9

Short-Term Borrowings - Schedul

Short-Term Borrowings - Schedule of Repurchase Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Securities sold under reverse repurchase agreements with customers	$ 164,174	$ 84,167
Maturity Overnight | Financial Assets Sold under Agreement to Repurchase | Mortgage Backed Securities, Other
Short-term Debt [Line Items]
Securities sold under reverse repurchase agreements with customers	$ 164,174	$ 84,167

Federal Reserve Bank Borrowin_2

Federal Reserve Bank Borrowings (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Amount borrowed	$ 0	$ 0
Federal Reserve Bank Advances [Member]
Available line of credit	$ 436,400,000	$ 367,800,000

Subordinated Debentures Issue_3

Subordinated Debentures Issued to Capital Trust - Schedule of Subordinated Debentures Issued to Capital Trusts (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Subordinated Debentures Issued to Capital Trusts
Subordinated debentures	$ 25,774	$ 25,774

Subordinated Debentures Issue_4

Subordinated Debentures Issued to Capital Trust - Additional information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2006	Dec. 31, 2020	Dec. 31, 2019
Subordinated Borrowing [Line Items]
Subordinated debentures issued to capital trust		$ 25,774	$ 25,774
Subordinated Debentures
Subordinated Borrowing [Line Items]
Aggregate liquidation amount	$ 25,000
Interest rate	6.98%	1.81%	3.51%
90-day LIBOR | Subordinated Debentures
Subordinated Borrowing [Line Items]
Spread on variable rate	1.60%

Subordinated Notes (Details)

Subordinated Notes (Details) - USD ($)	Jun. 10, 2020	Aug. 08, 2016	Dec. 31, 2020	Dec. 31, 2019
Debt instrument, interest rate terms	The notes are due June 15, 2030, and have a fixed interest rate of 5.50% until June 15, 2025, at which time the rate becomes floating at a rate expected to be equal to three-month term Secured Overnight Financing Rate (SOFR) plus 5.325%	The notes are due August 15, 2026, and have a fixed interest rate of 5.25% until August 15, 2021, at which time the rate becomes floating at a rate equal to three-month LIBOR plus 4.087%.
Public offering and sale of subordinated notes	$ 75,000,000	$ 75,000,000
Amortization of debt discount (Premium)			$ 608,000	$ 434,000
Subordinated Note Interest Rate	5.50%	5.25%
Subordinated borrowing, interest rate			5.84%	5.89%
Senior Subordinated Notes
Proceeds from issuance of senior long-term debt	$ 73,500,000	$ 73,500,000
Payment of financing and stock issuance costs	$ 1,500,000	$ 1,500,000
Debt Instrument, Interest Rate, Stated Percentage	5.325%
Expected life of the notes	5 years	5 years
Senior Subordinated Notes | 90-day LIBOR
Debt Instrument, Basis Spread on Variable Rate		4.087%

Subordinated Notes - Schedule o

Subordinated Notes - Schedule of Subordinated Borrowing (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Subordinated Notes
Subordinated notes	$ 150,000	$ 75,000
Less: unamortized debt issuance costs	1,603	724
Subordinated Debt	$ 148,397	$ 74,276

Income Taxes - Schedule of prov

Income Taxes - Schedule of provision for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Taxes currently payable	$ 25,259	$ 15,375	$ 19,291
Deferred income taxes (benefit)	(11,480)	1,074	(4,450)
Income taxes	$ 13,779	$ 16,449	$ 14,841

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Allowance for loan losses	$ 12,711	$ 9,188
Interest on nonperforming loans	142	161
Accrued expenses	894	821
Write-down of foreclosed assets	131	185
Write-down of fixed assets	114	50
Income recognized for tax in excess of book	8,830
Partnership tax credits	11	732
Deferred income	885	509
Difference in basis for acquired assets and liabilities	1,532	2,540
Deferred Tax Assets, Gross, Total	25,250	14,186
Deferred tax liabilities
Tax depreciation in excess of book depreciation	(5,988)	(5,986)
FHLB stock dividends	(368)	(817)
Prepaid expenses	(898)	(891)
Unrealized gain on available-for-sale securities	(6,869)	(2,671)
Unrealized gain on cash flow derivatives	(8,830)	(6,853)
Other	(258)	(233)
Deferred Tax Liabilities, Gross, Total	(23,211)	(17,451)
Net deferred tax (liability)		$ (3,265)
Net deferred tax asset	$ 2,039

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent	(0.50%)	(0.50%)	(0.80%)
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	(3.80%)	(3.60%)	(3.40%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	1.40%	1.30%	1.10%
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	0.80%	0.10%	0.20%
Effective Income Tax Rate Reconciliation, Percent	18.90%	18.30%	18.10%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Taxes
Retained earnings for which no deferred income tax liability had been recognized	$ 17.5	$ 17.5
Unrecorded deferred income tax liability	$ 3.9	$ 3.9

Disclosures About Fair Value _3

Disclosures About Fair Value of Financial Instruments - Fair Value, Assets Measured on Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Agency mortgage-backed securities
Recurring Assets, Fair Value Disclosure	$ 169,940,000	$ 165,042,000
Agency collateralized mortgage obligations
Recurring Assets, Fair Value Disclosure	176,621,000	151,950,000
States and political subdivisions securities
Recurring Assets, Fair Value Disclosure	47,325,000	35,125,000
Small Business Administration securities
Recurring Assets, Fair Value Disclosure	21,047,000	22,058,000
Interest Rate Derivative Asset
Recurring Assets, Fair Value Disclosure	5,062,000	31,476,000
Interest Rate Derivative Liability
Recurring Assets, Fair Value Disclosure	(5,454,000)	(1,547,000)
Fair Value, Inputs, Level 1
Securities at fair value	0	0
Fair Value, Inputs, Level 2 | Agency mortgage-backed securities
Recurring Assets, Fair Value Disclosure	169,940,000	165,042,000
Fair Value, Inputs, Level 2 | Agency collateralized mortgage obligations
Recurring Assets, Fair Value Disclosure	176,621,000	151,950,000
Fair Value, Inputs, Level 2 | States and political subdivisions securities
Recurring Assets, Fair Value Disclosure	47,325,000	35,125,000
Fair Value, Inputs, Level 2 | Small Business Administration securities
Recurring Assets, Fair Value Disclosure	21,047,000	22,058,000
Fair Value, Inputs, Level 2 | Interest Rate Derivative Asset
Recurring Assets, Fair Value Disclosure	5,062,000	31,476,000
Fair Value, Inputs, Level 2 | Interest Rate Derivative Liability
Recurring Assets, Fair Value Disclosure	(5,454,000)	(1,547,000)
Fair Value, Inputs, Level 3
Securities at fair value	$ 0	$ 0

Disclosures About Fair Value _4

Disclosures About Fair Value of Financial Instruments - Fair Value, Assets and Liabilities Measured on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans Receivable Impaired
Non-recurring Assets, Fair Value Disclosure	$ 1,759	$ 635
Foreclosed assets held for sale
Non-recurring Assets, Fair Value Disclosure	945	1,112
Fair Value, Inputs, Level 3 | Loans Receivable Impaired
Non-recurring Assets, Fair Value Disclosure	1,759	635
Fair Value, Inputs, Level 3 | Foreclosed assets held for sale
Non-recurring Assets, Fair Value Disclosure	$ 945	$ 1,112

Disclosures About Fair Value _5

Disclosures About Fair Value of Financial Instruments - Schedule Of Financial Instruments Fair Value (Details) $ in Thousands	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Unrecognized financial instruments (net of contractual value) | Commitments to Originate Loans
Fair Value Hierarchy Level	3	3
Unrecognized financial instruments (net of contractual value) | Letter of Credit
Financial Instruments Owned Carrying Amount	$ 84	$ 109
Financial Instruments, Owned, at Fair Value	$ 84	$ 109
Fair Value Hierarchy Level	3	3
Unrecognized financial instruments (net of contractual value) | Line of Credit
Fair Value Hierarchy Level	3	3
Financial Assets | Loans Receivable
Financial Instruments Owned Carrying Amount	$ 4,296,804	$ 4,153,982
Financial Instruments, Owned, at Fair Value	$ 4,303,909	$ 4,129,984
Fair Value Hierarchy Level	3	3
Financial Assets | Cash and Cash Equivalents
Financial Instruments Owned Carrying Amount	$ 563,729	$ 220,155
Financial Instruments, Owned, at Fair Value	$ 563,729	$ 220,155
Fair Value Hierarchy Level	1	1
Financial Assets | Mortgage loans held for sale
Financial Instruments Owned Carrying Amount	$ 17,780	$ 9,242
Financial Instruments, Owned, at Fair Value	$ 17,780	$ 9,242
Fair Value Hierarchy Level	2	2
Financial Assets | Interest Receivable
Financial Instruments Owned Carrying Amount	$ 12,793	$ 13,530
Financial Instruments, Owned, at Fair Value	$ 12,793	$ 13,530
Fair Value Hierarchy Level	3	3
Financial Assets | Investment in FHLBank stock and other interest-earning assets
Financial Instruments Owned Carrying Amount	$ 9,806	$ 13,473
Financial Instruments, Owned, at Fair Value	$ 9,806	$ 13,473
Fair Value Hierarchy Level	3	3
Financial Liabilities
Fair Value Hierarchy Level	3
Financial Liabilities | Junior Subordinated Debt
Financial Instruments Owned Carrying Amount	$ 25,774	$ 25,774
Financial Instruments, Owned, at Fair Value	25,774	$ 25,774
Fair Value Hierarchy Level		3
Financial Liabilities | Subordinated Debt
Financial Instruments Owned Carrying Amount	148,397	$ 74,276
Financial Instruments, Owned, at Fair Value	$ 157,032	$ 76,875
Fair Value Hierarchy Level	2	2
Financial Liabilities | Deposits
Financial Instruments Owned Carrying Amount	$ 4,516,903	$ 3,960,106
Financial Instruments, Owned, at Fair Value	$ 4,523,586	$ 3,963,875
Fair Value Hierarchy Level	3	3
Financial Liabilities | Short-term Debt
Financial Instruments Owned Carrying Amount	$ 165,692	$ 312,324
Financial Instruments, Owned, at Fair Value	$ 165,692	$ 312,324
Fair Value Hierarchy Level	3	3
Financial Liabilities | Accrued interest payable
Financial Instruments Owned Carrying Amount	$ 2,594	$ 4,250
Financial Instruments, Owned, at Fair Value	$ 2,594	$ 4,250
Fair Value Hierarchy Level	3	3

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities - Non-designated Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (264,000)	$ (104,000)	$ 25,000
Interest Rate Swap | Not Designated as Hedging Instrument | Third Parties
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 142,800	$ 96,000

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities - Cash Flow Hedges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivatives and Hedging Activities
Interest rate swap interest income	$ 7,700,000	$ 3,100,000
Non-interest income related to changes in the fair value of derivative	0	$ 0
Non-interest income related to changes in the fair value of derivative	$ 45,900,000

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities - Fair value and location (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments		$ 30,056
Derivative Asset
Total derivatives not designated as hedging instruments, Assets	$ 5,062	1,420
Derivative Liability
Total derivatives not designated as hedging instruments, Liabilities	5,454	1,547
Interest Rate Swap | Prepaid expenses and other current assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments		30,056
Interest rate products | Prepaid expenses and other current assets
Derivative Asset
Total derivatives not designated as hedging instruments, Assets	5,062	1,420
Interest rate products | Accrued expenses and other liabilities
Derivative Liability
Total derivatives not designated as hedging instruments, Liabilities	$ 5,454	$ 1,547

Derivatives and Hedging Activ_6

Derivatives and Hedging Activities - Cash Flow Hedge on Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amount of Gain Recognized In AOCI | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest rate swap, net of income taxes	$ 6,691	$ 13,857	$ 9,345

Derivatives and Hedging Activ_7

Derivatives and Hedging Activities - Cash Flow Hedge on Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest Income | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest rate swap, net of income taxes	$ 7,676	$ 3,082	$ 673

Derivatives and Hedging Activ_8

Derivatives and Hedging Activities - Agreements with Derivative Counterparties (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Loan Level Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Counterparties Collateral	$ 5,300,000
Net Liability Position | Balance Sheet Hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Counterparties Collateral	$ 391,000
Net Liability Position | Loan Level Swap | Commercial Lending Customer
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Counterparties Collateral		$ 1,100,000

Derivatives and Hedging Activ_9

Derivatives and Hedging Activities - Additional Information (Details) - Interest Rate Swap	12 Months Ended
	Dec. 31, 2020USD ($)derivativeloan	Dec. 31, 2019USD ($)loanderivative	Oct. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Participating Mortgage Loans, Mortgage Obligations, Amount	$ 27,700,000	$ 37,400,000
Number of Participation loans purchased | loan	4	5
Cash flow hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount			$ 400,000,000
Derivative, Fixed Interest Rate			3.018%
Expected interest income on termination	$ 2,000,000
Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Interest Rate Derivatives Held | derivative	19	19
Valley Bank | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 584,000
Number of Interest Rate Derivatives Held | derivative	2

Commitments and Credit Risk - O

Commitments and Credit Risk - Outstanding Commitments to Originate Loans (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Credit Risk
Outstanding commitments to originate loans	$ 46.6	$ 92.4

Commitments and Credit Risk - M

Commitments and Credit Risk - Mortgage Loans in Process of Origination (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Credit Risk
Mortgage loans in the process of origination	$ 85.9	$ 69.3

Commitments and Credit Risk - L

Commitments and Credit Risk - Letters of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Credit Risk
Letters of Credit Outstanding, Amount	$ 16.1	$ 26.3

Commitments and Credit Risk -_2

Commitments and Credit Risk - Lines of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Letters of Credit Outstanding, Amount	$ 16.1	$ 26.3
Commercial Lines of Credit
Letters of Credit Outstanding, Amount	1,000	1,200
Openend Consumer Lines of Credit
Letters of Credit Outstanding, Amount	$ 164.5	$ 155.8

Commitments and Credit Risk_ Cr

Commitments and Credit Risk: Credit Risk - Secured Loans (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Credit Risk
Loans and Leases Receivable, Collateral for Secured Borrowings	$ 804.1	$ 725

Additional Cash Flow Informat_3

Additional Cash Flow Information - Schedule of Cash Flow, Supplemental Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income taxes paid	$ 13,779	$ 16,449	$ 14,841
Noncash Investing and Financing Activities
Real estate acquired in settlement of loans	1,707	12,729	12,044
Sale and financing of foreclosed assets	625	1,340	2,578
Conversion of premises and equipment to foreclosed assets	80	1,135
Dividends declared but not paid	4,676	4,849	4,528
Additional Cash Payment Information
Interest paid	42,221	53,922	37,091
Income taxes paid	$ 18,755	$ 5,719	$ 2,569

Employee Benefits (Details)

Employee Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 01, 2020	Jul. 01, 2019
Employee Benefits
Employer contributions charged to expense	$ 2.1	$ 1.8	$ 1.3
Percentage of employer maximum total contributions	5.00%
Funded status of the plan (as a percent)				92.50%	93.70%
Percentage of employer's matching contribution of the employee's compensation	100.00%
Percentage of employee's compensation on which employer matches	3.00%
Percentage of employer's matching contribution of the employee's compensation	50.00%
Percentage of employee's compensation on which employer matches	2.00%
Employer contributions charged to expense	$ 1.6	$ 1.4	$ 1.4

Stock Compensation Plans - Addi

Stock Compensation Plans - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020shares	Dec. 31, 2019shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding	971,107	807,868
Ratio of shares utilized for awards other than stock options and stock appreciation rights	2.5
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
2003 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	598,224
Number of options outstanding	31,591
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	700,000
Number of options outstanding	384,866
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	800,000
Number of options outstanding	554,650

Stock Compensation Plans - Sche

Stock Compensation Plans - Schedule of Share-based Compensation, Stock Options, Activity (Details) - $ / shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	245,350	436,900	614,850	77,512
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable	971,107	807,868	773,236	682,799
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 48.079	$ 49.139	$ 43.886	$ 38.860
Granted from 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			1,000
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable			1,000	588,086
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price			$ 52.500
Exercised
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable	21,436	125,894	81,940
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 33.805	$ 33.031	$ 27.597
Forfeited from terminated plan(s)
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable	6,875	17,424
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 38.849	$ 44.163
Forfeited from current plan(s)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	4,800	8,450	600
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable	4,800	8,450	600
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 57.513	$ 55	$ 55
Forfeited from 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			13,773
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable			13,773
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price			$ 45.692
Termination of 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			90,285
Available to grant from 2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			800,000
Granted from 2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	196,350	186,400	185,750
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable	196,350	186,400	185,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 41.740	$ 60.086	$ 55.297

Stock Compensation Plans - Sc_2

Stock Compensation Plans - Schedule of Fair Value Option Pricing Model Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Compensation Plans
Expected dividends per share	$ 1.36	$ 1.36	$ 1.27
Risk-free interest rate	0.35%	1.59%	2.86%
Expected life of options	5 years	5 years	5 years
Expected volatility	29.32%	25.15%	17.61%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.30	$ 11.20	$ 8.30

Stock Compensation Plans - Sc_3

Stock Compensation Plans - Schedule of Share-based Compensation, Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	971,107	807,868
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 48.079	$ 49.139
Share based compensation stock option weighted average remaining contractual term	7 years 2 months 23 days	7 years 6 months 14 days
Granted
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	196,350
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 41.740
Exercised
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	21,436
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 30.805
Forfeited
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	11,675
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 46.523
Balance, End of Period
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	363,695
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 42.583
Balance, End of Period | Options exercisable
Share based compensation stock option weighted average remaining contractual term	4 years 11 months 12 days

Stock Compensation Plans - Opti

Stock Compensation Plans - Options Granted and Intrinsic Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Compensation Plans
Share Based Compensation Arrangement By Share Based Payment Award Options Granted Number	196,350	186,400	186,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 371,000	$ 3,100,000	$ 2,200,000
Proceeds from Stock Options Exercised	661,000	4,158,000	2,224,000
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	257,000	2,700,000	1,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	4,500,000	11,500,000	4,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 2,900,000	$ 6,600,000	$ 3,900,000

Stock Compensation Plans - Sc_4

Stock Compensation Plans - Schedule of Nonvested Share Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Nonvested options Member
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	607,412	552,377
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Exercise Price	$ 51.370	$ 54.610
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Grant Date Fair Value	$ 8.981	$ 9.509
Granted
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	196,350
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Exercise Price	$ 41.740
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Grant Date Fair Value	$ 7.296
Vested this period Member
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	134,140
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Exercise Price	$ 50.441
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Grant Date Fair Value	$ 8.662
Nonvested options forfeited Member
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	7,175
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Exercise Price	$ 54.655
Share Based Compensation Arrangement by Share Based Payment Award Nonvested Weighted Average Grant Date Fair Value	$ 9.501

Stock Compensation Plans - Nonv

Stock Compensation Plans - Nonvested Options Granted Unrecognized Compensation Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Stock Compensation Plans
Nonvested Options Granted Unrecognized Compensation Costs	$ 4.6

Stock Compensation Plans - Shar

Stock Compensation Plans - Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	971,107	807,868
Share based compensation stock option weighted average remaining contractual term	7 years 2 months 23 days	7 years 6 months 14 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 48.079	$ 49.139	$ 43.886	$ 38.860
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	363,695
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 42.583
Range of Exercise Prices Member | $16.810 to 29.640 Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	64,043
Share based compensation stock option weighted average remaining contractual term	2 years 1 month 28 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 25.598
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	64,043
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 25.598
Exercise price range, minimum	16.810
Exercise price range, maximum	$ 29.640
Range of Exercise Prices Member | $32.590 to 38.610 Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	62,056
Share based compensation stock option weighted average remaining contractual term	3 years 7 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 33.001
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	61,181
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 32.921
Exercise price range, minimum	32.590
Exercise price range, maximum	$ 38.610
Range of Exercise Prices Member | $41.300 to 47.800 Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	282,357
Share based compensation stock option weighted average remaining contractual term	8 years 6 months 21 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 41.613
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	59,816
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 41.335
Exercise price range, minimum	41.300
Exercise price range, maximum	$ 47.800
Range of Exercise Prices Member | $50.710 to 52.500 Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	204,251
Share based compensation stock option weighted average remaining contractual term	6 years 1 month 9 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 51.656
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	133,496
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 51.415
Exercise price range, minimum	50.710
Exercise price range, maximum	$ 52.500
Range of Exercise Prices Member | $55.000 to 60.150 Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	358,400
Share based compensation stock option weighted average remaining contractual term	8 years 4 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 57.762
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	45,159
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 55.306
Exercise price range, minimum	55
Exercise price range, maximum	$ 60.150

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income - Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, before tax	$ 68,850	$ 41,771
Tax effect	(15,699)	(9,525)
Net-of-tax amount	53,151	32,246
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, before tax	30,126	11,715
Net unrealized gain on derivatives used for cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, before tax	$ 38,724	$ 30,056

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income - Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 5,283	$ 48	$ 2
Affected Line Item in the Statements of Income Member | Net realized gains on available-for-sale securities (total reclassified amount before tax)
Unrealized gains on available-for-sale securities reclassified out of AOCI	78	(62)	2
Affected Line Item in the Statements of Income Member | Amortization of realized gain on termination of cash flow hedge
Change in fair value of cash flow hedge available-for-sale securities reclassified out of AOCI	6,764	0	0
Affected Line Item in the Statements of Income Member | Tax Expense (Benefit)
Income taxes on unrealized gains on available-for-sale securities reclassified out of AOCI	$ (1,559)	$ 14	$ 0

Regulatory Matters - Schedule o

Regulatory Matters - Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Total capital Member | Great Southern Bancorp, Inc. Member
Actual Capital Amount	$ 800,388	$ 698,085
Actual Capital Ratio	17.20%	15.00%
Capital Required for Capital Adequacy	$ 373,132	$ 372,387
Capital Required for Capital Adequacy to Risk Weighted Assets	8	8
Total capital Member | Great Southern Bank Member
Actual Capital Amount	$ 694,047	$ 650,280
Actual Capital Ratio	14.90%	14.00%
Capital Required for Capital Adequacy	$ 373,058	$ 372,316
Capital Required for Capital Adequacy to Risk Weighted Assets	8	8
Capital Required to be Well Capitalized	$ 466,322	$ 465,395
Capital Required to be Well Capitalized to Risk Weighted Assets	10	10
Tier I capital Member | Great Southern Bancorp, Inc. Member
Actual Capital Amount	$ 594,645	$ 582,791
Actual Capital Ratio	12.70%	12.50%
Capital Required for Capital Adequacy	$ 279,849	$ 279,290
Capital Required for Capital Adequacy to Risk Weighted Assets	6	6
Tier I capital Member | Great Southern Bank Member
Actual Capital Amount	$ 638,304	$ 609,986
Actual Capital Ratio	13.70%	13.10%
Capital Required for Capital Adequacy	$ 279,793	$ 279,237
Capital Required for Capital Adequacy to Risk Weighted Assets	6	6
Capital Required to be Well Capitalized	$ 373,058	$ 372,316
Capital Required to be Well Capitalized to Risk Weighted Assets	8	8
Tier I leverage capital Member | Great Southern Bancorp, Inc. Member
Actual Capital Amount	$ 594,645	$ 582,791
Actual Capital Ratio	10.90%	11.80%
Capital Required for Capital Adequacy	$ 217,223	$ 198,320
Capital Required for Capital Adequacy to Risk Weighted Assets	4	4
Tier I leverage capital Member | Great Southern Bank Member
Actual Capital Amount	$ 638,304	$ 609,986
Actual Capital Ratio	11.80%	12.30%
Capital Required for Capital Adequacy	$ 217,170	$ 198,010
Capital Required for Capital Adequacy to Risk Weighted Assets	4	4
Capital Required to be Well Capitalized	$ 271,463	$ 247,512
Capital Required to be Well Capitalized to Risk Weighted Assets	5	5
Common equity Tier I capital Member | Great Southern Bancorp, Inc. Member
Actual Capital Amount	$ 569,645	$ 557,791
Actual Capital Ratio	12.20%	12.00%
Capital Required for Capital Adequacy	$ 209,887	$ 209,468
Capital Required for Capital Adequacy to Risk Weighted Assets	4.5	4.5
Common equity Tier I capital Member | Great Southern Bank Member
Actual Capital Amount	$ 638,304	$ 609,986
Actual Capital Ratio	13.70%	13.10%
Capital Required for Capital Adequacy	$ 209,845	$ 209,428
Capital Required for Capital Adequacy to Risk Weighted Assets	4.5	4.5
Capital Required to be Well Capitalized	$ 303,109	$ 302,507
Capital Required to be Well Capitalized to Risk Weighted Assets	6.5	6.5

Summary of Unaudited Quarterl_3

Summary of Unaudited Quarterly Operating Results: Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Summary of Unaudited Quarterly Operating Results
Interest Income	$ 52,619	$ 53,599	$ 54,011	$ 57,474	$ 58,726	$ 60,187	$ 58,723	$ 57,358	$ 56,142	$ 52,982	$ 49,943	$ 46,882
Interest expense	8,042	9,431	10,556	12,536	13,784	14,263	13,802	12,753	11,585	9,997	8,731	7,444
Provision for loan losses	1,500	4,500	6,000	3,871	650	1,950	1,600	1,950	1,950	1,300	1,950	1,950
Net realized gains (losses) on available-for-sale securities			78		(72)			10		2
Noninterest income	9,956	9,466	8,261	7,367	7,695	8,655	7,157	7,450	7,220	14,604	7,459	6,935
Noninterest expense	31,073	31,988	29,349	30,815	29,535	28,725	28,383	28,495	28,774	28,309	29,915	28,312
Provision for income taxes	4,172	3,692	3,164	2,751	4,559	4,172	3,720	3,998	3,765	5,464	2,967	2,645
Net income available to common shareholders	$ 17,788	$ 13,454	$ 13,203	$ 14,868	$ 17,893	$ 19,732	$ 18,375	$ 17,612	$ 17,288	$ 22,516	$ 13,839	$ 13,466
Earnings per common share - diluted	$ 1.28	$ 0.96	$ 0.93	$ 1.04	$ 1.24	$ 1.38	$ 1.28	$ 1.23	$ 1.21	$ 1.57	$ 0.97	$ 0.95

Condensed Parent Company Stat_3

Condensed Parent Company Statements - Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Condensed Balance Sheet Statements, Captions [Line Items]
Cash	$ 92,403	$ 99,299
Prepaid expenses and other assets	58,889	74,984
Total Assets	5,526,420	5,015,072
Subordinated debentures issued to capital trust	148,397	74,276
Subordinated notes	148,397	74,276
Additional paid-in capital	35,004	33,510
Retained earnings	541,448	537,167
Accumulated other comprehensive income	53,151	32,246
Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash	111,250	58,726
Investment in subsidiary bank	698,398	650,329
Deferred and accrued income taxes	157	111
Prepaid expenses and other assets	883	868
Total Assets	810,688	710,034
Accounts payable and accrued expenses	6,776	6,918
Subordinated debentures issued to capital trust	25,774	25,774
Subordinated notes	148,397	74,276
Common Stock	138	143
Additional paid-in capital	35,004	33,510
Retained earnings	541,448	537,167
Accumulated other comprehensive income	53,151	32,246
Total Assets and Liabilities	$ 810,688	$ 710,034

Condensed Parent Company Stat_4

Condensed Parent Company Statements - Condensed Income Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Income Statements, Captions [Line Items]
Interest Expense	$ 40,565	$ 54,602	$ 37,757
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Dividends from subsidiary bank	40,000	32,000	34,000
Interest and dividend income	5
Loss on other investments		(23)
Total income	40,005	31,977	34,000
Operating Expenses	2,197	2,044	1,793
Interest Expense	7,459	5,397	5,050
Total expense	9,656	7,441	6,843
Income before income tax and equity in undistributed earnings of subsidiaries	30,349	24,536	27,157
Credit for income taxes	(1,800)	(1,381)	(1,204)
Income before equity in earnings of subsidiaries	32,149	25,917	28,361
Equity in undistributed earnings of subsidiaries	27,164	47,695	38,748
Net income	$ 59,313	$ 73,612	$ 67,109

Condensed Parent Company Stat_5

Condensed Parent Company Statements - Condensed Cash Flow Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Prepaid expenses and other assets	$ 17,163	$ 1,336	$ (3,002)
Accounts Payable and Other Accrued Liabilities	29,783	24,904
Net cash provided by operating activities	46,048	86,419	94,195
Net cash provided by investing activities	(131,346)	(295,149)	(381,323)
Proceeds from issuance of subordinated notes	73,513	0	0
Net cash used in financing activities	428,872	226,143	247,617
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net income	59,313	73,612	67,109
Equity in undistributed earnings of subsidiary	(27,164)	(47,695)	(38,748)
Compensation expense for stock option grants	1,153	922	737
Amortization of interest rate derivative and deferred costs on subordinated notes	608	434	154
Loss on other investments		23
Prepaid expenses and other assets	(15)	(3)	13
Accounts Payable and Other Accrued Liabilities	31	226	182
Income taxes	(46)	300	(278)
Net cash provided by operating activities	33,880	27,819	29,169
Return of principal - other investments		2
Net cash provided by investing activities		2
Purchases of the Company's common stock	(22,104)	(849)	(903)
Proceeds from issuance of subordinated notes	73,513
Dividends paid	(33,426)	(29,052)	(15,819)
Stock options exercised	661	4,158	2,224
Net cash used in financing activities	18,644	(25,743)	(14,498)
Increase in Cash	52,524	2,078	14,671
Cash, Beginning of Year		58,726	56,648	$ 41,977
Cash, End of Year	111,250	58,726	56,648
Interest paid	$ 7,349	$ 5,424	$ 5,001

Condensed Parent Company Stat_6

Condensed Parent Company Statements - Condensed Statement of Comprehensive Income - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Statement of Income Captions [Line Items]
Change in fair value of cash flow hedge, net of taxes of $0, $0 and $93 for 2019, 2018 and 2017, respectively	$ 11,914	$ 13,857	$ 9,345
Parent Company [Member]
Condensed Statement of Income Captions [Line Items]
Net Income	59,313	73,612	67,109
Comprehensive income (loss) of subsidiaries	20,905	22,619	8,114
Comprehensive Income parent	$ 80,218	$ 96,231	$ 75,223

Sale of Branches and Related _2

Sale of Branches and Related Deposits (Details)	Jul. 20, 2018USD ($)Center
Number of banking centers sold | Center	4
Deposits | West Gate Bank
Proceeds from Sale of Other Productive Assets	$ 56,000,000
Transaction expense | West Gate Bank
Proceeds from Sale of Other Productive Assets	165,000
Pre-tax gain | West Gate Bank
Proceeds from Sale of Other Productive Assets	$ 7,400,000