Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		$ 71,348	$ 72,738
Noninterest Income (out-of-scope of Topic 606)		26,958	18,465
Total noninterest income		98,306	91,202
Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		22,608	25,464
Wealth management fees(a)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)	[1]	20,816	20,180
Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		15,222	15,115
Card-based fees(b)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		9,607	9,295
Other revenue
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		3,096	2,684
Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		20,736	19,449
Noninterest Income (out-of-scope of Topic 606)		14,066	7,945
Corporate and Commercial Specialty | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		76	125
Corporate and Commercial Specialty | Wealth management fees(a)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		15,806	15,099
Corporate and Commercial Specialty | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		3,551	3,498
Corporate and Commercial Specialty | Card-based fees(b)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		515	434
Corporate and Commercial Specialty | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		788	293
Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		50,535	53,098
Noninterest Income (out-of-scope of Topic 606)		7,115	5,177
Community, Consumer, and Business | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		22,529	25,336
Community, Consumer, and Business | Wealth management fees(a)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		5,010	5,080
Community, Consumer, and Business | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		11,665	11,599
Community, Consumer, and Business | Card-based fees(b)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		9,045	8,812
Community, Consumer, and Business | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		2,286	2,271
Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		77	191
Noninterest Income (out-of-scope of Topic 606)		5,777	5,342
Risk Management and Shared Services | Insurance commissions and fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		3	3
Risk Management and Shared Services | Wealth management fees(a)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		0	0
Risk Management and Shared Services | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		5	19
Risk Management and Shared Services | Card-based fees(b)
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		47	49
Risk Management and Shared Services | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest Income (in-scope of Topic 606)		23	120
Operating Segments [Member] | Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Total noninterest income		34,802	27,394
Operating Segments [Member] | Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Total noninterest income		57,650	58,275
Operating Segments [Member] | Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Total noninterest income		$ 5,854	$ 5,533

[1] (a) Includes trust, asset management, brokerage, and annuity fees.