Loans and Allowance for Credit Losses - PCD Loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Non-credit related discount	$ 29,100	$ 21,500
Landmark Community Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	66,662
PCD allowance for credit loss at acquisition	(2,359)
Non-credit related discount	(2,577)
Fair value of PCD loans	61,726
Triumph Bancshares Inc
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	121,284
PCD allowance for credit loss at acquisition	(11,092)
Non-credit related discount	(1,594)
Fair value of PCD loans	108,598
Spirit of Texas Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	74,851
PCD allowance for credit loss at acquisition	(5,100)
Non-credit related discount	(1,377)
Fair value of PCD loans	68,374
Commercial | Landmark Community Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	11,046
PCD allowance for credit loss at acquisition	(350)
Non-credit related discount	(160)
Fair value of PCD loans	10,536
Commercial | Triumph Bancshares Inc
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	40,466
PCD allowance for credit loss at acquisition	(2,999)
Non-credit related discount	(279)
Fair value of PCD loans	37,188
Commercial | Spirit of Texas Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	8,258
PCD allowance for credit loss at acquisition	(1,911)
Non-credit related discount	(378)
Fair value of PCD loans	5,969
Real Estate | Landmark Community Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	55,549
PCD allowance for credit loss at acquisition	(2,008)
Non-credit related discount	(2,415)
Fair value of PCD loans	51,126
Real Estate | Triumph Bancshares Inc
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	80,803
PCD allowance for credit loss at acquisition	(8,093)
Non-credit related discount	(1,314)
Fair value of PCD loans	71,396
Real Estate | Spirit of Texas Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	66,534
PCD allowance for credit loss at acquisition	(3,187)
Non-credit related discount	(998)
Fair value of PCD loans	62,349
Credit cards | Landmark Community Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	0
PCD allowance for credit loss at acquisition	0
Non-credit related discount	0
Fair value of PCD loans	0
Credit cards | Triumph Bancshares Inc
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	0
PCD allowance for credit loss at acquisition	0
Non-credit related discount	0
Fair value of PCD loans	0
Credit cards | Spirit of Texas Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	0
PCD allowance for credit loss at acquisition	0
Non-credit related discount	0
Fair value of PCD loans	0
Other Consumer and Other | Landmark Community Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	67
PCD allowance for credit loss at acquisition	(1)
Non-credit related discount	(2)
Fair value of PCD loans	64
Other Consumer and Other | Triumph Bancshares Inc
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	15
PCD allowance for credit loss at acquisition	0
Non-credit related discount	(1)
Fair value of PCD loans	14
Other Consumer and Other | Spirit of Texas Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Line Items]
Unpaid principal balance	59
PCD allowance for credit loss at acquisition	(2)
Non-credit related discount	(1)
Fair value of PCD loans	$ 56