Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 43,164,000	$ 47,585,000	$ 20,503,000
Adjustments to reconcile income to net cash provided by operating activities:
Provision for loan losses	3,000,000	23,100,000	6,050,000
Depreciation	6,118,000	6,004,000	5,356,000
Deferred tax expense	3,145,000	(3,377,000)	1,611,000
Amortization of net discount on securities	3,399,000	4,180,000	4,663,000
Net accretion of discount on acquired loans	(1,142,000)	(3,766,000)	(4,175,000)
Net change in deferred loan origination fees and costs	617,000	8,811,000	2,682,000
Amortization of core deposits and other intangible assets	1,417,000	1,485,000	1,896,000
Net amortization (accretion) of lease marks	0	83,000	(6,000)
Amortization of software implementation costs	1,063,000	1,028,000	1,036,000
Accretion of fair value premium on acquired deposits	(45,000)	(151,000)	(288,000)
Amortization of fair value discount on subordinated debt	256,000	258,000	261,000
Amortization of issuance costs on subordinated debt	93,000	45,000	0
Amortization of fair value discount on convertible notes payable	746,000	752,000	761,000
Accretion of fair value premium on Federal Home Loan Bank advances	0	(165,000)	(57,000)
Increase in cash surrender value of bank-owned life insurance	(1,276,000)	(1,283,000)	(1,308,000)
Impairment of premises and equipment	0	678,000	0
Impairment of other real estate owned and foreclosed assets	217,000	418,000	1,076,000
Federal Home Loan Bank stock dividends	(407,000)	(468,000)	(311,000)
Share-based compensation expense	2,998,000	2,335,000	2,147,000
Decrease in fair value of mortgage servicing rights	5,606,000	22,280,000	11,930,000
Net gain on sales of available-for-sale securities	0	(153,000)	(1,583,000)
Net loss (gain) on sales of loans held-for-investment	701,000	1,180,000	(511,000)
Net loss on disposal of premises and equipment	76,000	519,000	207,000
Net gain on other real estate owned and foreclosed assets activity	(824,000)	(320,000)	(312,000)
Net gain on bank-owned life insurance	0	0	(464,000)
Net gain on sales of loans held-for-sale	(61,403,000)	(74,642,000)	(23,910,000)
Origination of loans held-for-sale	(2,165,255,000)	(2,471,066,000)	(1,203,526,000)
Proceeds from sales of loans held-for-sale	2,292,828,000	2,422,778,000	1,161,914,000
Changes in operating assets and liabilities:
Accrued interest receivable	655,000	(2,862,000)	(1,682,000)
Prepaid expenses and other assets	(6,769,000)	(17,116,000)	5,405,000
Accrued interest payable	(223,000)	398,000	467,000
Accrued expenses and other liabilities	(15,646,000)	30,905,000	14,065,000
Net cash provided by (used in) operating activities	113,109,000	(547,000)	3,897,000
Cash flows from investing activities:
Net cash paid for acquisitions	0	(7,019,000)	0
Proceeds from maturities of held-to-maturity securities	13,835,000	24,433,000	18,084,000
Purchases of available-for-sale securities	(248,736,000)	(101,812,000)	(149,423,000)
Proceeds from sale or maturities of available-for-sale securities	131,899,000	185,704,000	194,169,000
Loan originations, net of repayments	(215,281,000)	(863,138,000)	(294,975,000)
Proceeds from the sale of loans held-for-sale previously classified as held-for-investment	18,544,000	97,832,000	14,438,000
Purchases of premises and equipment	(3,455,000)	(6,155,000)	(6,908,000)
Proceeds from the sale of premises and equipment	5,000	2,945,000	1,757,000
Proceeds from sales of other real estate owned and foreclosed assets	2,089,000	6,729,000	2,686,000
Proceeds from bank-owned life insurance	0	0	1,337,000
Purchases of restricted equity securities	(57,000)	(8,704,000)	(12,157,000)
Proceeds from the sale or redemption of restricted equity securities	7,400,000	6,431,000	13,917,000
Purchase of other investments	(686,000)	(155,000)	(82,000)
Proceeds from the sale or redemption of other investments	519,000	1,000	10,000
Net cash provided by (used in) investing activities	(293,924,000)	(662,908,000)	(217,147,000)
Cash flows from financing activities:
Net change in deposits	701,444,000	663,750,000	468,677,000
Net change in securities sold under agreements to repurchase	(23,278,000)	47,261,000	(14,678,000)
Proceeds from Federal Home Loan Bank advances	0	0	871,000,000
Repayments of Federal Home Loan Bank advances	(30,411,000)	(6,000,000)	(1,027,712,000)
Proceeds from other borrowings	0	1,159,000,000	6,000,000
Repayments of other borrowings	0	(1,180,581,000)	(11,000,000)
Proceeds from Subordinated debt	0	39,067,000	0
Proceeds from issuance of common stock, net of issuance costs	(456,000)	0	1,268,000
Issuance of treasury stock	0	(31,000)	358,000
Purchase of treasury stock	0	(1,564,000)	(36,706,000)
Net cash provided by (used in) financing activities	647,299,000	720,902,000	257,207,000
Net increase in cash and cash equivalents	466,484,000	57,447,000	43,957,000
Cash and cash equivalents, beginning of year	201,978,000	144,531,000	100,574,000
Cash and cash equivalents, end of year	668,462,000	201,978,000	144,531,000
Supplemental disclosures of cash flow information:
Interest paid on deposits	8,753,000	16,481,000	22,870,000
Interest paid on borrowed funds	5,667,000	5,529,000	5,693,000
Cash paid for income taxes, net	6,601,000	8,003,000	520,000
Non-cash investing and financing activities:
Net change in unrealized gain (loss) on available-for-sale securities	(9,870,000)	9,613,000	16,515,000
Loan charge-offs	4,861,000	4,900,000	5,049,000
Premises and equipment transferred to other real estate owned and foreclosed assets	1,038,000	0	0
Loans transferred to other real estate owned and foreclosed assets	2,577,000	3,110,000	6,478,000
Other assets transferred to Premises and equipment	170,000	0	0
Mortgage servicing rights resulting from sale or securitization of mortgage loans	$ 23,854,000	$ 22,421,000	$ 14,745,000