Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	$ 240,106	$ 228,825	$ 227,208
Noninterest income	465,532	454,397	436,063
Noninterest expense out of scope of ASC 606	14,083	17,296	17,332
Noninterest expense	13,523	17,050	17,756
Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	10,203	135	169
Noninterest income	127,860	113,242	115,567
Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	8,209
Noninterest income	10,413	0	0
Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	5,750	283	169
Noninterest income	87,221	78,406	75,165
Other noninterest income
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	215,944	228,407	226,870
Noninterest income	240,038	262,749	245,331
Consumer Banking
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	196,643	188,365	180,448
Noninterest expense within the scope of ASC 606	(1,088)	0	0
Consumer Banking | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	112,733	108,883	111,222
Consumer Banking | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	2,204
Consumer Banking | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	81,465	78,119	74,992
Consumer Banking | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	241	1,363	(5,766)
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	14,210	15,615	12,368
Noninterest expense within the scope of ASC 606	546	(246)	424
Commercial Banking | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	4,924	4,224	4,176
Commercial Banking | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0
Commercial Banking | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	6	4	4
Commercial Banking | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	9,280	11,387	8,188
Enterprise Services
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	14,573	21,592	16,039
Noninterest expense within the scope of ASC 606	(18)	0	0
Enterprise Services | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0	0	0
Enterprise Services | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0
Enterprise Services | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0	0	0
Enterprise Services | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	$ 14,573	$ 21,592	$ 16,039