Consolidated statements of cash flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 190,301	$ 63,629	$ 83,814
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of fixed assets and software	8,416	7,536	5,176
Amortization of core deposit and other intangibles	5,473	5,323	4,339
Capitalization of mortgage servicing rights	(39,018)	(47,025)	(42,151)
Net change in fair value of mortgage servicing rights	3,503	47,660	26,299
Stock-based compensation expense	10,282	10,214	7,089
Provision for credit losses	(38,995)	94,606	7,053
Provision for credit losses on unfunded commitments	(1,998)	13,361	0
Provision for mortgage loan repurchases	(766)	2,607	362
Amortization (accretion) of premiums and discounts on acquired loans, net	853	(3,788)	(8,556)
Accretion of discounts and amortization of premiums on securities, net	8,777	7,382	3,026
Gain from securities, net	(324)	(1,631)	(57)
Originations of loans held for sale	(6,300,892)	(6,650,258)	(4,540,652)
Repurchases of loans held for sale	(487)	0	(9,919)
Proceeds from sale of loans held for sale	6,387,110	6,487,809	4,662,728
Gain on sale and change in fair value of loans held for sale	(161,964)	(270,802)	(100,228)
Net (gain) loss or write-downs of other real estate owned	(2,504)	1,491	(545)
(Gain) loss on other assets	(323)	90	104
Relief of goodwill	0	0	100
Provision for deferred income taxes	30,770	(25,530)	(1,916)
Earnings on bank-owned life insurance	(1,542)	(1,556)	(242)
Changes in:
Operating leases	(969)	2,664	0
Other assets and interest receivable	59,283	(57,316)	(44,938)
Accrued expenses and other liabilities	(100,108)	43,532	13,019
Net cash provided by (used in) operating activities	54,878	(270,002)	63,905
Activity in available-for-sale securities:
Sales	8,855	146,494	24,498
Maturities, prepayments and calls	296,256	220,549	113,018
Purchases	(847,212)	(424,971)	(151,425)
Net change in loans	(457,042)	4,383	(364,975)
Net change in commercial loans held for sale	147,276	114,031	0
Sales of FHLB stock	4,294	0	0
Purchases of FHLB stock	(5,279)	(515)	(2,544)
Proceeds from sale of mortgage servicing rights	0	0	29,160
Purchases of premises and equipment	(6,102)	(5,934)	(6,812)
Proceeds from the sale of premises and equipment	0	0	1,275
Proceeds from the sale of other real estate owned	9,396	6,937	3,860
Net cash acquired in business combinations	0	248,447	171,032
Net cash (used in) provided by investing activities	(849,558)	310,136	(182,913)
Cash flows from financing activities:
Net increase in demand deposits	1,685,033	1,519,868	249,348
Net decrease in time deposits	(306,173)	(328,035)	(75,004)
Net increase (decrease) in securities sold under agreements to repurchase	8,517	5,262	(908)
Payments on FHLB advances	0	(250,000)	0
Proceeds from FHLB advances	0	0	68,235
Issuance of subordinated debt, net of issuance costs	0	98,189	0
Payments on subordinated debt	(60,000)	0	0
Accretion of subordinated debt fair value premium and amortization of issuance costs, net	17	(397)	0
(Payments on) proceeds from other borrowings	(15,000)	15,000	0
Share based compensation withholding payments	(10,158)	(1,510)	(6,097)
Net proceeds from sale of common stock under employee stock purchase program	1,480	978	804
Repurchase of common stock	(7,595)	0	0
Dividends paid	(21,583)	(14,264)	(10,045)
Noncontrolling interest distribution	(16)	(8)	0
Net cash provided by financing activities	1,274,522	1,045,083	226,333
Net change in cash and cash equivalents	479,842	1,085,217	107,325
Cash and cash equivalents at beginning of the period	1,317,898	232,681	125,356
Cash and cash equivalents at end of the period	1,797,740	1,317,898	232,681
Supplemental cash flow information:
Interest paid	41,238	48,679	55,051
Taxes paid	61,693	20,419	25,290
Supplemental noncash disclosures:
Transfers from loans to other real estate owned	5,262	2,746	5,487
Transfers from other real estate owned to premises and equipment	0	841	0
Transfers to premises and equipment	0	0	4,290
Loans provided for sales of other real estate owned	704	305	166
Transfers from loans to loans held for sale	10,408	11,483	7,981
Transfers from loans held for sale to loans	86,315	55,766	12,259
Stock consideration paid in business combination	0	480,867	0
Dividends declared not paid on restricted stock units	400	238	149
Decrease to retained earnings for adoption of new accounting standards	0	25,018	1,309
Right-of-use assets obtained in exchange for operating lease liabilities	970	2,393	37,916
Proceeds from Life Insurance Policy	$ 0	$ 715	$ 0