Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 23,931		$ 19,652	$ 47,549	$ 26,231
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization				2,533	2,719
Deferred taxes				(643)	(2,034)
Stock-based compensation				423	472
Provision for credit losses	(4,257)	$ (2,500)	(49)	(6,756)	12,658	$ 16,047
Write-downs of other real estate owned and other repossessed assets				504	764
Gains on sale of mortgage loans held for sale	(1,907)		(1,753)	(4,340)	(2,236)
Securities gains, net				(60)	(1,045)
Change in fair market value of equity securities	(280)		(373)	(52)	(141)
Gains on sale of assets, net				(227)	(30)
Proceeds from sale of mortgage loans held for sale				196,989	104,642
Funding of mortgage loans held for sale				(174,303)	(130,226)
Amortization of securities premiums and discounts, net				3,824	2,416
Change in cash surrender value of bank owned life insurance				(682)	(676)
Payment of operating lease liabilities				(855)	(855)
Mortgage servicing rights:
Fair value adjustments				(421)	1,305
New servicing assets created				(1,410)	(560)
Changes in:
Accrued interest receivable				351	(22)
Other assets				1,047	(626)
Accrued interest payable				375	1,669
Other liabilities				6,098	10,197
Net cash provided by operating activities				69,944	24,622
Securities available-for-sale (AFS):
Purchase of AFS securities				(559,810)	(376,320)
Proceeds from sales of AFS securities				1,080	64,293
Proceeds from prepayments, calls, and maturities of AFS securities				187,189	179,209
Securities held-to-maturity (HTM):
Proceeds from maturities of HTM securities				0	517
Change in loans, net				106,337	(294,547)
Purchase of premises and equipment				(612)	(573)
Proceeds from sale and retirement of premises and equipment				812	0
Purchase of stock by Federal Home Loan Bank				1,020	66
Proceeds from sale of other real estate owned and repossessed assets				1,128	1,351
Net cash used in investing activities				(262,856)	(426,004)
Cash flows from financing activities:
Change in deposits, net				307,620	566,737
Change in repurchase agreements and federal funds purchased, net				14,706	62,184
Proceeds from Federal Home Loan Bank advances				0	25,000
Payments on advances from Federal Home Loan Bank				(10)	(25,010)
Payment of finance lease liabilities				(8)	(7)
Issuance of common stock				480	457
Repurchase of common stock				0	(1,099)
Dividends paid				(13,691)	(13,478)
Net cash provided by financing activities				309,097	614,784
Net increase in cash and cash equivalents				116,185	213,402
Cash and cash equivalents at beginning of period		$ 338,235		338,235	264,683	264,683
Cash and cash equivalents at end of period	$ 454,420		$ 478,085	454,420	478,085	$ 338,235
Supplemental disclosures:
Income taxes paid				11,030	8,645
Interest paid				7,462	13,292
Non-cash activities:
Loans to facilitate the sale of other real estate owned and repossessed assets				475	1,582
Common stock dividends accrued, paid in subsequent quarter				239	233
Real estate acquired in settlement of loans				$ 251	$ 1,862