Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Contract with Customer, Asset, Gross, Noncurrent	$ 0				$ 0				$ 0	$ 0
Contract with Customer, Liability, Noncurrent	0				0				0	0
Revenue from contract with customer									55,316,000	52,961,000	$ 54,273,000
Other sources of noninterest income									154,061,000	157,948,000	203,475,000
Total noninterest income	$ 63,013,000	$ 51,474,000	$ 52,759,000	$ 42,131,000	$ 41,695,000	$ 46,502,000	$ 48,268,000	$ 74,444,000	209,377,000	210,909,000	257,748,000
Deposit service charges and related fee income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									34,940,000	35,223,000	36,049,000
Card income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									3,708,000	3,953,000	4,250,000
Wealth management fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									16,668,000	13,785,000	13,974,000
Consumer and Business Banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									40,200,000	39,027,000	39,792,000
Other sources of noninterest income									17,720,000	46,580,000	14,659,000
Total noninterest income									57,920,000	85,607,000	54,451,000
Consumer and Business Banking | Deposit service charges and related fee income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									21,327,000	22,474,000	24,109,000
Consumer and Business Banking | Card income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									3,032,000	3,196,000	3,465,000
Consumer and Business Banking | Wealth management fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									15,841,000	13,357,000	12,218,000
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									15,067,000	13,511,000	14,017,000
Other sources of noninterest income									119,555,000	96,776,000	96,072,000
Total noninterest income									134,622,000	110,287,000	110,089,000
Commercial Banking | Deposit service charges and related fee income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									13,564,000	12,326,000	11,476,000
Commercial Banking | Card income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									676,000	757,000	785,000
Commercial Banking | Wealth management fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									827,000	428,000	1,756,000
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									49,000	423,000	464,000
Other sources of noninterest income									16,786,000	14,592,000	92,744,000
Total noninterest income									16,835,000	15,015,000	93,208,000
Other | Deposit service charges and related fee income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									49,000	423,000	464,000
Other | Card income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0	0
Other | Wealth management fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									$ 0	$ 0	$ 0