Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
OPERATING ACTIVITIES
Net income	$ 136,038	$ 103,619
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	24,148	16,019
Provision for credit loss expense	53,049	16,364
(Benefit) provision for credit losses on unfunded commitments	(8,000)	950
Gain on sale of investments	(32,485)	(5,563)
Net accretion of investment securities and assets	(30,078)	(22,663)
Net amortization on borrowings	271	182
Stock-based compensation expense	7,577	6,249
Gain on sale of foreclosed assets held for sale	(400)	(16)
Gain on sale of mortgage loans held for sale	(14,993)	(8,257)
Gain on sale of other intangibles	(301)	0
Gain on sale of branches	(8,094)	0
Fair value write-down of closed branches	1,465	0
Deferred income taxes	4,616	4,940
Income from bank owned life insurance	(3,245)	(2,136)
Originations of mortgage loans held for sale	(470,797)	(282,204)
Proceeds from sale of mortgage loans held for sale	423,858	282,861
Changes in assets and liabilities:
Interest receivable	(18,021)	(1,494)
Lease right-of-use assets	5,995	(2,469)
Other assets	(19,676)	18,911
Accrued interest and other liabilities	70,270	(5,326)
Income taxes payable	(34,233)	2,553
Net cash provided by operating activities	86,964	122,520
INVESTING ACTIVITIES
Net originations of loans	(318,795)	(302,151)
Proceeds from sale of loans	4,600	0
(Increase) decrease in due from banks - time	(7)	395
Purchases of premises and equipment, net	(19,784)	(21,689)
Proceeds from sale of foreclosed assets held for sale	6,173	9,870
Proceeds from sale of available-for-sale securities	1,201,778	449,107
Proceeds from maturities of available-for-sale securities	2,048,453	296,409
Purchases of available-for-sale securities	(2,386,878)	(383,416)
Proceeds from maturities of held-to-maturity securities	5,932	25,406
Purchases of held-to-maturity securities	(16,997)	0
Proceeds from bank owned life insurance death benefits	763	1,310
Disposition of assets and liabilities held for sale	181,261	1,393
Purchase of Reliance Bancshares, Inc.	0	(37,017)
Net cash provided by investing activities	706,499	39,617
FINANCING ACTIVITIES
Net change in deposits	561,185	(107,806)
Repayments of subordinated debentures	(5,927)	0
Dividends paid on preferred stock	(26)	(326)
Dividends paid on common stock	(37,606)	(30,265)
Net change in other borrowed funds	96,090	(178,756)
Net change in federal funds purchased and securities sold under agreements to repurchase	236,880	20,532
Net shares cancelled under stock compensation plans	(3,171)	(3,030)
Shares issued under employee stock purchase plan	956	1,312
Retirement of preferred stock	0	(42,000)
Repurchases of common stock	(93,307)	0
Net cash provided by (used in) financing activities	755,074	(340,339)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	1,548,537	(178,202)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	996,623	833,458
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 2,545,160	$ 655,256