Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	$ 75,496	$ 55,899	$ 156,814	$ 105,706
Noninterest income	133,054	109,718	270,017	213,222
Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	2,863	0	5,848	24
Noninterest income	22,832	27,842	57,429	54,120
Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	5,940		12,330
Noninterest income	6,206	0	12,357	0
Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	2,398	21	4,876	(1,253)
Noninterest income	20,636	20,496	42,321	39,155
Other noninterest income
Disaggregation of Revenue [Line Items]
Revenue out of scope of ASC 606	64,295	55,878	133,760	106,935
Noninterest income	83,380	61,380	157,910	119,947
Consumer Banking
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	53,781	47,530	106,762	91,855
Consumer Banking | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	18,812	26,707	49,030	51,900
Consumer Banking | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	266		27
Consumer Banking | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	18,223	20,475	37,404	39,105
Consumer Banking | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	16,480	348	20,301	850
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	3,745	3,238	7,129	8,815
Commercial Banking | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	1,157	1,135	2,551	2,196
Commercial Banking | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0		0
Commercial Banking | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	15	0	41	1,303
Commercial Banking | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	2,573	2,103	4,537	5,316
Enterprise Services
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	32	3,051	(688)	6,846
Enterprise Services | Fees and service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0	0	0	0
Enterprise Services | Wealth management revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0		0
Enterprise Services | Card and ATM revenue
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	0	0	0	0
Enterprise Services | Other noninterest income
Disaggregation of Revenue [Line Items]
Revenues within the scope of 606	$ 32	$ 3,051	$ (688)	$ 6,846