Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES
Net income	$ 547,459	$ 491,723	$ 457,371
Adjustments to reconcile net income to cash provided by operating activities:
(Benefit) provision for credit losses	(36,835)	58,352	31,441
Deferred tax expense (benefit)	(7,586)	(25,535)	54,598
Change in current taxes payable	(731,741)	(5,894)	(19,564)
Depreciation	106,585	108,641	103,828
Change in accrued interest payable	(1,493)	(8,683)	14,412
Change in income earned not collected	11,457	(21,982)	(4,151)
Gain on acquisitions	(32)	(100,000)	(3,592)
Realized gains on investment securities available for sale, net	(33,119)	(60,253)	(7,115)
Marketable equity securities gains, net	(34,081)	(29,395)	(20,625)
Origination of loans held for sale	(1,123,312)	(1,042,292)	(698,044)
Proceeds from sale of loans held for sale	1,035,822	1,045,937	731,803
Gain on sale of loans	(32,719)	(37,594)	(15,183)
Loss on sale of other real estate	(1,207)	4,056	2,664
Net amortization of premiums and discounts	11,151	(8,513)	(27,263)
Amortization of intangible assets	25,582	32,801	23,861
Net increase (decrease) in other liabilities	(13,658)	(12,149)	(5,927)
Net change in other assets	(12,910)	(7,286)	(24,274)
Net change in other liabilities	6,854	(6,115)	(15,992)
Net cash provided by operating activities	(283,783)	375,819	578,248
INVESTING ACTIVITIES
Net change in loans outstanding	423,257	(3,850,129)	(1,320,851)
Payments to Acquire Available-for-sale Securities	(6,375,349)	(8,667,406)	(4,705,038)
Purchases of investment securities held to maturity	(1,401,220)	(1,633,165)	(223,598)
Purchases of marketable equity securities	(1,563)	(333,140)	(26,166)
Proceeds from maturities of investment securities held to maturity	809,421	301,347	341,077
Proceeds from maturities of investment securities available for sale	2,454,722	2,791,291	2,345,512
Proceeds from Sale of Available-for-sale Securities	1,366,909	4,585,002	2,308,856
Proceeds from sales of marketable equity securities	29,796	352,835	56,749
Net change in overnight investments	(4,767,324)	(3,204,363)	(65,181)
Proceeds from sale of portfolio loans	0	13,368	24,247
Net Payment to the FDIC for Termination of Loss Share Agreements	(16,103)	(99,468)	0
Proceeds from Sale of Other Real Estate Held-for-investment	40,524	28,280	25,918
Proceeds from Sale of Property, Plant, and Equipment	1,194	1,369	132
Additions to premises and equipment	(107,367)	(133,384)	(121,077)
Other investing activities	(25,323)	0	0
Business acquisitions, net of cash acquired	0	(59,999)	(236,728)
Net cash (used) provided by investing activities	(7,568,426)	(9,907,562)	(1,596,148)
FINANCING ACTIVITIES
Net change in time deposits	(406,226)	(1,010,190)	284,611
Net change in demand and other interest-bearing deposits	8,382,531	9,989,107	1,154,815
Net change in short-term borrowings	(52,386)	(96,746)	(27,703)
Repayment of long-term obligations	(54,332)	(86,737)	(73,284)
Origination of long-term obligations	0	400,000	200,000
Net proceeds from subordinated notes issuance	0	345,849	0
Net proceeds from preferred stock issuance	0	339,937	0
Repurchase of common stock	0	(333,755)	(453,123)
Cash dividends paid	(41,612)	(30,393)	(18,137)
Net cash provided (used) by financing activities	7,827,975	9,517,072	1,067,179
Change in cash and due from banks	(24,234)	(14,671)	49,279
Cash and due from banks at beginning of period	362,048	376,719	327,440
Cash and due from banks at end of period	337,814	362,048	376,719
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Interest	62,169	104,567	78,230
Income taxes	870,467	116,583	83,038
Premises and equipment acquired through finance leases and other financing arrangements	13,979	11,635	14,639
Dividends declared but not paid	0	4,613	4,256
Transfer of loans held for sale to loans held for investment	3,574	5,950	0
Loans held for sale exchanged for investment securities	230,537	11,137	0
Transfer of loans held for investment to loans held for sale	87,814	48,628	60,005
Transfer of investment securities available for sale to (from) held to maturity	451,684	1,460,745
Transfer of investment securities available for sale to (from) held to maturity			(2,080,617)
Transfers of premises and equipment to other real estate	$ 13,776	$ 15,187	$ 7,045