Summary of Significant Accounting Policies - Recent Accounting and Regulatory Pronouncements (Details)		12 Months Ended
	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2016 USD ($)
Right to use asset		$ 87,389,000
Lease Liability		88,846,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, New Commercial Loan Platform		1,100,000
Allowance for credit losses		61,991,000	$ 55,798,000	$ 48,075,000		$ 40,355,000
Increase in allowance for credit losses		(723,000)	$ (1,134,000)	$ (821,000)
Internal use software
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, Front Capture Software Product		$ 171,000
ASU 2016- 02 | Adjustments
Right to use asset					$ 82,200,000
Lease Liability					82,200,000
ASU 2016-13
Number of loan segments | loan		10
Historical losses term		10 years
ASU 2016-13 | Minimum | Forecast adjustments
Allowance for credit losses	$ 105,000,000
Increase in allowance for credit losses	35,000,000
Estimated decline in equity, net of tax	33,500,000
ASU 2016-13 | Maximum | Forecast adjustments
Allowance for credit losses	120,000,000
Increase in allowance for credit losses	50,000,000
Estimated decline in equity, net of tax	$ 45,200,000
2018-15
Capitalized implementation costs related to internal use software		$ 1,300,000
2018-15 | Internal use software
Capitalized implementation costs related to internal use software					1,300,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, New Commercial Loan Platform					1,100,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, Front Capture Software Product					$ 171,000