Business Combinations - Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($)	Feb. 22, 2021	Sep. 25, 2020	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Assets
Goodwill			$ 112,773,000		$ 104,992,000
LINCO Bancshares, Inc.
Assets
Cash and due from banks	$ 130,561,000
Investment securities	119,498,000
Loans	828,976,000
Allowance for credit losses	(2,073,000)
Other real estate owned	9,350,000
Premises and equipment	29,800,000
Goodwill	6,370,000		$ 6,369,000	$ 8,900,000
Other assets	45,275,000
Total assets acquired	1,170,699,000
Liabilities
Deposits	990,410,000
Securities sold under agreements to repurchase	0
FHLB advances	27,916,000
Other borrowings	0
Lease liability	794,000
Other liabilities	3,888,000
Total liabilities assumed	1,023,008,000
Net assets acquired	147,691,000
Consideration paid
Consideration payable in cash	103,500,000	$ 103,500,000
Common stock	44,191,000
Total Consideration Paid	147,691,000
LINCO Bancshares, Inc. | Acquired Book Value
Assets
Cash and due from banks	130,561,000
Investment securities	119,234,000
Loans	838,377,000
Allowance for credit losses	(8,656,000)
Other real estate owned	8,435,000
Premises and equipment	23,440,000
Goodwill	20,503,000
Other assets	43,697,000
Total assets acquired	1,175,714,000
Liabilities
Deposits	988,329,000
Securities sold under agreements to repurchase	0
FHLB advances	26,941,000
Other borrowings	0
Lease liability	0
Other liabilities	4,498,000
Total liabilities assumed	1,019,768,000
Net assets acquired	155,946,000
LINCO Bancshares, Inc. | Fair Value Adjustments
Assets
Cash and due from banks	0
Investment securities	264,000
Loans	(9,401,000)
Allowance for credit losses	6,583,000
Other real estate owned	915,000
Premises and equipment	6,360,000
Goodwill	(14,133,000)
Other assets	1,578,000
Total assets acquired	(5,015,000)
Liabilities
Deposits	2,081,000
Securities sold under agreements to repurchase	0
FHLB advances	975,000
Other borrowings	0
Lease liability	794,000
Other liabilities	(610,000)
Total liabilities assumed	3,240,000
Net assets acquired	(8,255,000)
LINCO Bancshares, Inc. | Core Deposit Intangibles
Assets
Intangible assets	2,148,000
LINCO Bancshares, Inc. | Core Deposit Intangibles | Acquired Book Value
Assets
Intangible assets	123,000
LINCO Bancshares, Inc. | Core Deposit Intangibles | Fair Value Adjustments
Assets
Intangible assets	2,025,000
LINCO Bancshares, Inc. | Right of Use Asset
Assets
Intangible assets	794,000
LINCO Bancshares, Inc. | Right of Use Asset | Acquired Book Value
Assets
Intangible assets	0
LINCO Bancshares, Inc. | Right of Use Asset | Fair Value Adjustments
Assets
Intangible assets	$ 794,000