Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest income
Interest and fees on loans	$ 174,228	$ 191,895	$ 348,277	$ 416,681
Interest and dividends on investment securities
Taxable	8,840	16,103	15,855	36,375
Tax-exempt	14,366	14,616	28,528	29,498
Other interest	1,826	2,231	3,521	5,535
Total interest income	199,260	224,845	396,180	488,090
Interest expense
Interest on deposits	4,609	13,178	10,519	49,844
Interest on federal funds purchased and securities sold under agreements to repurchase	30	51	55	420
Interest on other short-term funding	7	5	13	40
Interest on PPPLF funding	0	676	0	676
Interest on FHLB advances	9,524	15,470	19,017	33,096
Interest on long-term funding	5,575	5,593	11,160	11,200
Total interest expense	19,745	34,973	40,764	95,276
Net interest income	179,515	189,872	355,416	392,814
Provision for credit losses	(35,004)	61,000	(58,009)	114,001
Net interest income after provision for credit losses	214,519	128,872	413,425	278,813
Noninterest income
Noninterest Income In Scope of Topic 606	53,522	66,933	105,284	138,282
Capital markets, net	5,696	6,910	13,814	14,845
Mortgage banking, net	8,128	12,263	32,054	18,407
Bank and corporate owned life insurance	3,088	3,625	5,791	6,719
Asset gains (losses), net(a)	(14)	157,361	4,796	157,284
Investment securities gains (losses), net	24	3,096	(16)	9,214
Gains on sale of branches, net(b)	36	0	1,038	0
Other	2,918	2,737	6,059	5,090
Total noninterest income	73,443	254,490	168,786	352,796
Noninterest expense
Personnel	106,994	111,350	211,020	225,551
Technology	20,236	21,174	40,975	41,973
Occupancy	14,679	14,464	30,835	30,532
Business development and advertising	4,970	3,556	9,366	9,382
Equipment	5,481	5,312	10,999	10,751
Legal and professional	6,661	5,058	13,191	10,217
Loan and foreclosure costs	2,671	3,605	4,891	6,725
FDIC assessment	3,600	5,250	8,350	10,750
Other intangible amortization	2,203	2,872	4,439	5,686
Other	6,979	10,766	15,755	24,030
Total noninterest expense	174,475	183,407	349,821	375,598
Income (loss) before income taxes	113,487	199,955	232,389	256,012
Income tax expense (benefit)	22,480	51,238	47,082	61,457
Net income	91,007	148,718	185,307	194,555
Preferred stock dividends	4,875	4,144	10,082	7,945
Net income available to common equity	$ 86,131	$ 144,573	$ 175,226	$ 186,611
Earnings per common share
Basic	$ 0.56	$ 0.94	$ 1.14	$ 1.21
Diluted	$ 0.56	$ 0.94	$ 1.13	$ 1.20
Average common shares outstanding
Basic	152,042	152,393	152,198	153,547
Diluted	153,381	153,150	153,473	154,360
Wealth management fees
Noninterest income
Noninterest Income In Scope of Topic 606	$ 22,706	$ 20,916	$ 45,120	$ 41,732
Service charges and deposit account fees
Noninterest income
Noninterest Income In Scope of Topic 606	15,549	11,484	30,404	26,706
Card-based fees
Noninterest income
Noninterest Income In Scope of Topic 606	11,009	8,922	20,773	18,529
Card-based fees	10,982	8,893	20,725	18,490
Other fee-based revenue
Noninterest income
Noninterest Income In Scope of Topic 606	4,173	3,181	8,826	6,277
Card-based fees	4,244	4,774	8,840	9,272
Insurance commissions and fees
Noninterest income
Noninterest Income In Scope of Topic 606	86	22,430	161	45,038
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	15,999	17,929	30,464	38,190
Provision for credit losses	(55,999)	41,858	(101,610)	77,579
Noninterest income
Total noninterest income	3,195	165,242	9,379	171,465
Noninterest expense
Total noninterest expense	19,810	9,733	40,086	33,843
Income (loss) before income taxes	35,065	110,350	61,492	69,065
Income tax expense (benefit)	7,823	34,065	14,560	25,451
Net income	$ 27,242	$ 76,285	$ 46,932	$ 43,613