Consolidated Statements of Cash Flows - (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash Flows From Operating Activities:
Net Income	$ 91,462	$ 51,979
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(6,206)	34,047
Provision for unfunded commitments	(1,203)	3,052
Depreciation and amortization	2,263	2,238
Mortgage servicing rights gain	(139)	0
Gains on sale of loans	(8,656)	(4,023)
Securities premium amortization (discount accretion), net	5,486	2,931
Origination of loans held for sale	(713,771)	(307,790)
Proceeds from sale of loans held for sale	754,683	300,087
Net increase in cash surrender value of BOLI	(787)	(1,242)
Deferred income tax (benefit) expense	144	(7,560)
Net gain on sale of investment securities	(539)	(1,535)
Stock-based compensation expense	3,823	2,423
Net tax benefits from stock compensation	0	(313)
(Increase) decrease in other assets	(13,561)	(20,365)
Increase (decrease) in other liabilities	(1,111)	(5,612)
Net cash provided by operating activities	111,888	48,317
Cash Flows From Investing Activities:
Purchases of available-for-sale investment securities	(768,909)	(209,460)
Proceeds from maturities of available-for-sale securities	166,731	170,754
Proceeds from sale/call of available-for-sale securities	52,022	119,988
Purchases of Federal Reserve and Federal Home Loan Bank stock	(98)	(9,074)
Sale of Federal Reserve and Federal Home Loan Bank stock	6,169	4,250
Proceeds from sale of SBA PPP loans	169,778	0
Net change in loans	320,029	(481,672)
Net change in premises and equipment	(4,350)	(2,965)
Net cash used in investing activities	(58,628)	(408,179)
Cash Flows From Financing Activities:
Increase in deposits	(170,156)	711,581
Net change in customer repurchase agreements	(7,076)	218
Increase in short-term borrowings	0	50,000
Proceeds from long-term borrowings	0	50,098
Repayment of long-term borrowings	(50,000)	0
Proceeds from issuance of common stock	327	0
Proceeds from employee stock purchase plan	0	382
Common stock repurchased	(62)	(44,168)
Cash dividends paid	(19,126)	(14,180)
Net cash provided by financing activities	(246,093)	753,931
Net Decrease In Cash and Cash Equivalents	(192,833)	394,069
Cash and Cash Equivalents at Beginning of Period	1,789,055	241,973
Cash and Cash Equivalents at End of Period	1,596,222	636,042
Supplemental Cash Flows Information:
Interest paid	22,535	41,413
Income taxes paid	(30,986)	26,900
Non-Cash Investing Activities
Initial recognition of operating lease right-of-use assets	7,339	945
Transfers from loans to other real estate owned	0	6,750
Change in fair value of cash flow hedges	516	0
Change in fair value of investments	$ (15,295)	$ 0