Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Interest income
Interest and fees on loans	$ 174,643	$ 182,625	$ 522,920	$ 599,306
Interest and dividends on investment securities
Taxable	8,745	13,689	24,600	50,064
Tax-exempt	14,613	14,523	43,141	44,021
Other interest	2,281	2,238	5,802	7,774
Total interest income	200,282	213,075	596,462	701,165
Interest expense
Interest on deposits	4,427	10,033	14,945	59,877
Interest on federal funds purchased and securities sold under agreements to repurchase	48	34	103	454
Interest on other short-term funding	8	5	21	46
Interest on PPPLF funding	0	899	0	1,574
Interest on FHLB advances	8,962	14,375	27,979	47,471
Interest on long-term funding	3,163	5,580	14,323	16,780
Total interest expense	16,607	30,925	57,371	126,201
Net interest income	183,675	182,150	539,092	574,964
Provision for credit losses	(24,010)	43,009	(82,018)	157,009
Net interest income after provision for credit losses	207,685	139,141	621,110	417,954
Noninterest income
Noninterest Income In Scope of Topic 606	53,099	49,243	158,383	187,524
Capital markets, net	7,114	7,222	20,928	22,067
Mortgage banking, net	10,657	12,636	42,710	31,043
Bank and corporate owned life insurance	2,760	3,074	8,551	9,793
Asset gains (losses), net(a)	5,228	(339)	10,024	156,945
Investment securities gains (losses), net	0	7	(16)	9,222
Gains on sale of branches, net(b)	0	0	1,038	0
Other	2,116	2,232	8,176	7,321
Total noninterest income	82,076	75,545	250,862	428,342
Noninterest expense
Personnel	107,880	108,567	318,900	334,117
Technology	19,927	19,666	60,902	61,639
Occupancy	15,814	17,854	46,649	48,386
Business development and advertising	6,156	3,626	15,522	13,007
Equipment	5,200	5,399	16,199	16,150
Legal and professional	4,304	5,591	17,495	15,809
Loan and foreclosure costs	1,616	2,118	6,508	8,842
FDIC assessment	5,000	3,900	13,350	14,650
Other intangible amortization	2,203	2,253	6,642	7,939
Loss on prepayments of FHLB advances	0	44,650	0
Other	9,793	13,963	25,547	37,993
Total noninterest expense	177,892	227,587	527,713	603,184
Income (loss) before income taxes	111,870	(12,900)	344,259	243,112
Income tax expense (benefit)	23,060	(58,114)	70,142	3,342
Net income	88,809	45,214	274,117	239,769
Preferred stock dividends	4,155	5,207	14,236	13,152
Net income available to common equity	$ 84,655	$ 40,007	$ 259,880	$ 226,618
Earnings per common share
Basic	$ 0.56	$ 0.26	$ 1.70	$ 1.47
Diluted	$ 0.56	$ 0.26	$ 1.69	$ 1.46
Average common shares outstanding
Basic	150,046	152,440	151,473	153,175
Diluted	151,143	153,194	152,701	153,914
Wealth management fees
Noninterest income
Noninterest Income In Scope of Topic 606	$ 22,110	$ 21,152	$ 67,229	$ 62,884
Service charges and deposit account fees
Noninterest income
Noninterest Income In Scope of Topic 606	16,962	14,283	47,366	40,989
Card-based fees
Noninterest income
Noninterest Income In Scope of Topic 606	11,147	10,207	31,920	28,736
Card-based fees	11,113	10,195	31,838	28,685
Other fee-based revenue
Noninterest income
Noninterest Income In Scope of Topic 606	2,792	3,487	11,618	9,764
Card-based fees	3,929	4,968	12,769	14,240
Insurance commissions and fees
Noninterest income
Noninterest Income In Scope of Topic 606	88	114	250	45,153
Risk Management and Shared Services
Noninterest expense
Loss on prepayments of FHLB advances			44,650
Risk Management and Shared Services | ABRC
Noninterest income
Gains on sale of branches, net(b)			163,000
Operating Segments | Risk Management and Shared Services
Interest expense
Net interest income	19,047	16,472	49,511	54,662
Provision for credit losses	(43,107)	21,679	(144,717)	99,257
Noninterest income
Total noninterest income	3,077	5,182	12,457	176,646
Noninterest expense
Total noninterest expense	24,478	72,813	64,490	106,610
Income (loss) before income taxes	21,962	(89,005)	83,529	(19,895)
Income tax expense (benefit)	6,129	(72,278)	20,705	(46,817)
Net income	$ 15,833	$ (16,727)	$ 62,824	$ 26,922