Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Noninterest income	$ 38,018	$ 41,568	$ 78,572	$ 79,578
Noninterest expense	(104,561)	$ (98,237)	(206,171)	$ (202,433)
Noninterest income from contracts with customers within the scope of ASC 606
Disaggregation of Revenue [Line Items]
Noninterest income	7,119		14,764
Service charges and fees on deposit accounts
Disaggregation of Revenue [Line Items]
Noninterest income	4,462		8,925
Wealth management revenue
Disaggregation of Revenue [Line Items]
Noninterest income	1,268		2,052
Other charges and fees for customer services
Disaggregation of Revenue [Line Items]
Noninterest income	1,389		3,787
Noninterest income within the scope of other GAAP topics
Disaggregation of Revenue [Line Items]
Noninterest income	30,899		63,808
Other
Disaggregation of Revenue [Line Items]
Noninterest expense	$ (38)		$ 684