Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net (loss) income	$ (60,825)	$ 85,827
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	18,252	16,837
Provision for loan losses	188,007	5,192
Deferred income taxes	(21,442)	1,457
Gains on sale of securities, net		(2,250)
Trading securities revenue	(59)
Purchases of trading securities	(17,485)
Proceeds from sale of trading securities	17,051
Share-based compensation expense	13,734	4,357
Accretion of discount related to acquired loans	(21,039)	(6,518)
(Gains) losses on disposal of premises and equipment	(239)	3,723
Losses (gains) on sale of bank premises and other repossessed real estate	79	(380)
Net amortization of premiums on investment securities	5,523	3,325
Bank premises and other repossessed real estate write downs	350	487
Fair value adjustment for loans held for sale	(11,621)	730
Originations and purchases of loans held for sale	(796,272)	(327,348)
Proceeds from sales of loans held for sale	737,760	306,062
Gains on sales of loans held for sale	(20,202)	(4,314)
Bank owned life insurance income	(2,753)	(2,707)
Net change in:
Accrued interest receivable	(18,700)	(2,653)
Prepaid assets	(3,577)	(2,025)
Operating Leases	2,858	504
Bank owned life insurance	13,567	1,105
Derivative assets	(65,552)	(12,496)
Miscellaneous other assets	26,318	(24,031)
Accrued interest payable	(1,554)	1,449
Accrued income taxes	(5,121)	470
Derivative liabilities	98,885	25,865
Miscellaneous other liabilities	(6,075)	27,589
Net cash provided by operating activities	69,868	100,257
Cash flows from investing activities:
Proceeds from sales of investment securities available for sale		189,327
Proceeds from maturities and calls of investment securities available for sale	252,809	113,039
Proceeds from sales of other investment securities	42,034	45
Purchases of investment securities available for sale	(295,652)	(463,473)
Purchases of other investment securities	(28,744)	(23,566)
Net increase in loans	(1,045,044)	(214,785)
Net cash received from acquisitions	2,566,376
Recoveries of loans previously charged off	4,933	1,949
Purchases of premises and equipment	(9,082)	(8,116)
Proceeds from sale of bank premises and other repossessed real estate	2,862	4,428
Proceeds from sale of premises and equipment	9	8
Net cash provided by (used in) investing activities	1,490,501	(401,144)
Cash flows from financing activities:
Net increase in deposits	2,157,236	275,346
Net increase in federal funds purchased and securities sold under agreements to repurchase and other short-term borrowings	20,191	27,381
Proceeds from borrowings	500,000	700,001
Repayment of borrowings	(500,004)	(150,004)
Common stock issuance	385	343
Common stock repurchases	(32,160)	(82,103)
Dividends paid on common stock	(31,573)	(27,491)
Stock options exercised	560	402
Net cash provided by financing activities	2,114,635	743,875
Net increase in cash and cash equivalents	3,675,004	442,988
Cash and cash equivalents at beginning of period	688,704	408,983
Cash and cash equivalents at end of period	4,363,708	851,971
Cash paid for:
Interest	39,347	41,476
Income taxes	2,878	20,903
Initial measurement and recognition of operating lease assets in exchange for lease liabilities per ASU 2016-02		82,160
Recognition of operating lease assets in exchange for lease liabilities	5,121	4,950
Acquisitions:
Fair value of tangible assets acquired	18,910,560
Other intangible assets acquired	130,862
Liabilities assumed	17,380,016
Net identifiable assets acquired over liabilities assumed	600,483
Common stock issued in acquisition	2,246,327
Real estate acquired in full or in partial settlement of loans	$ 4,054	$ 7,632