Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	$ 51,762	$ 71,348
Noninterest income (out-of-scope of Topic 606)	43,581	26,958
Total noninterest income	95,343	98,306
Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	76	22,608
Wealth management fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	22,414	20,816
Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	14,855	15,222
Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	9,764	9,607
Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	4,653	3,096
Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	28,463	25,036
Noninterest income (out-of-scope of Topic 606)	14,568	13,697
Corporate and Commercial Specialty | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	24	76
Corporate and Commercial Specialty | Wealth management fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	22,414	20,106
Corporate and Commercial Specialty | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	4,905	3,551
Corporate and Commercial Specialty | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	435	515
Corporate and Commercial Specialty | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	685	788
Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	22,889	46,235
Noninterest income (out-of-scope of Topic 606)	23,239	7,115
Community, Consumer, and Business | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	50	22,529
Community, Consumer, and Business | Wealth management fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	0	710
Community, Consumer, and Business | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	9,935	11,665
Community, Consumer, and Business | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	9,325	9,045
Community, Consumer, and Business | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	3,579	2,286
Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	409	77
Noninterest income (out-of-scope of Topic 606)	5,775	6,146
Risk Management and Shared Services | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	2	3
Risk Management and Shared Services | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	15	5
Risk Management and Shared Services | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	4	47
Risk Management and Shared Services | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	389	23
Operating Segments [Member] | Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Total noninterest income	43,031	38,733
Operating Segments [Member] | Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Total noninterest income	46,128	53,350
Operating Segments [Member] | Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Total noninterest income	$ 6,184	$ 6,223