Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income
Interest and fees on loans	$ 174,049	$ 224,786
Interest and dividends on investment securities
Taxable	7,014	20,272
Tax-exempt	14,162	14,882
Other interest	1,694	3,304
Total interest income	196,920	263,244
Interest expense
Interest on deposits	5,909	36,666
Interest on federal funds purchased and securities sold under agreements to repurchase	26	368
Interest on other short-term funding	6	36
Interest on FHLB advances	9,493	17,626
Interest on long-term funding	5,585	5,607
Total interest expense	21,018	60,303
Net interest income	175,902	202,942
Provision for credit losses	(23,004)	53,001
Net interest income after provision for credit losses	198,906	149,941
Noninterest income
Noninterest Income In Scope of Topic 606	51,762	71,348
Capital markets, net	8,118	7,935
Mortgage banking, net	23,925	6,143
Bank and corporate owned life insurance	2,702	3,094
Asset gains (losses), net	4,809	(77)
Investment securities gains (losses), net	(39)	6,118
Gains on sale of branches, net(a)	1,002	0
Other	3,141	2,352
Total noninterest income	95,343	98,306
Noninterest expense
Personnel	104,026	114,200
Technology	20,740	20,799
Occupancy	16,156	16,069
Business development and advertising	4,395	5,826
Equipment	5,518	5,439
Legal and professional	6,530	5,160
Loan and foreclosure costs	2,220	3,120
FDIC assessment	4,750	5,500
Other intangible amortization	2,236	2,814
Other	8,775	13,263
Total noninterest expense	175,347	192,191
Income (loss) before income taxes	118,903	56,056
Income tax expense (benefit)	24,602	10,219
Net income	94,301	45,838
Preferred stock dividends	5,207	3,801
Net income available to common equity	$ 89,094	$ 42,037
Earnings per common share
Basic	$ 0.58	$ 0.27
Diluted	$ 0.58	$ 0.27
Average common shares outstanding
Basic	152,355	154,701
Diluted	153,688	155,619
Wealth management fees
Noninterest income
Noninterest Income In Scope of Topic 606	$ 22,414	$ 20,816
Service charges and deposit account fees
Noninterest income
Noninterest Income In Scope of Topic 606	14,855	15,222
Card-based fees
Noninterest income
Noninterest Income In Scope of Topic 606	9,764	9,607
Card-based fees	9,743	9,597
Other fee-based revenue
Noninterest income
Noninterest Income In Scope of Topic 606	4,653	3,096
Card-based fees	4,596	4,497
Insurance commissions and fess
Noninterest income
Noninterest Income In Scope of Topic 606	76	22,608
Operating Segments | Risk Management and Shared Services
Interest expense
Net interest income	14,465	20,261
Provision for credit losses	(45,612)	35,720
Noninterest income
Total noninterest income	6,184	6,223
Noninterest expense
Total noninterest expense	20,275	24,110
Income (loss) before income taxes	26,427	(41,285)
Income tax expense (benefit)	6,737	(8,613)
Net income	$ 19,690	$ (32,672)