Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	$ 49,011	$ 53,099	$ 152,974	$ 158,383
Noninterest income (out-of-scope of Topic 606)(b)	21,777	28,977	67,740	92,479
Total noninterest income	70,788	82,076	220,713	250,862
Whitnell
Disaggregation of Revenue [Line Items]
Gain (Loss) on Sale and Maturity of Other Investments, Before Tax				2,000
Wealth management fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	19,984	22,110	63,719	67,229
Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	15,029	16,962	48,392	47,366
Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	11,512	11,147	32,933	31,920
Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	2,486	2,880	7,930	11,868
Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	23,931	27,176	77,846	82,540
Noninterest income (out-of-scope of Topic 606)(b)	11,732	14,717	34,774	38,451
Corporate and Commercial Specialty | Wealth management fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	19,984	22,110	63,719	67,229
Corporate and Commercial Specialty | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	3,128	3,948	10,636	11,748
Corporate and Commercial Specialty | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	424	381	1,203	1,011
Corporate and Commercial Specialty | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	395	738	2,288	2,552
Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	24,503	25,803	74,642	74,984
Noninterest income (out-of-scope of Topic 606)(b)	2,241	11,250	17,431	42,366
Community, Consumer, and Business | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	11,896	13,009	37,743	35,591
Community, Consumer, and Business | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	10,970	10,707	31,629	30,830
Community, Consumer, and Business | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	1,637	2,088	5,270	8,563
Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	577	120	486	858
Noninterest income (out-of-scope of Topic 606)(b)	7,804	3,011	15,535	11,662
Risk Management and Shared Services | Service charges and deposit account fees
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	5	5	13	27
Risk Management and Shared Services | Card-based fees(a)
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	118	60	101	79
Risk Management and Shared Services | Other revenue
Disaggregation of Revenue [Line Items]
Noninterest income (in-scope of Topic 606)	454	55	373	752
Operating Segments [Member] | Corporate and Commercial Specialty
Disaggregation of Revenue [Line Items]
Total noninterest income	35,663	41,892	112,620	120,991
Operating Segments [Member] | Community, Consumer, and Business
Disaggregation of Revenue [Line Items]
Total noninterest income	26,745	37,053	92,072	117,351
Operating Segments [Member] | Risk Management and Shared Services
Disaggregation of Revenue [Line Items]
Total noninterest income	$ 8,381	$ 3,131	$ 16,021	$ 12,520