Loans, Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") Due to COVID-19 (Details) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2021 USD ($) Loan		Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Loan		Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Loan	Dec. 31, 2019 USD ($)
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Interest only period for Commercial loans					3 months
Suspended payments period for Retail loans					3 months
Total loans		$ 2,883,978			$ 2,883,978
Total loans	[1]							$ 2,733,678
Percentage of total loans, COVID-19 Accommodations					0.20%
Allowance for credit losses		46,799	[1]		$ 46,799	[1]			$ 26,148
Interest and fees on loans		30,132		$ 30,393	86,328		$ 92,020
Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans		$ 90,150			$ 90,150
Total loans								$ 169,782
Number of outstanding loans | Loan		826			826			1,483
Unaccreted net fees remaining at period end		$ 3,178			$ 3,178			$ 3,216
Allowance for credit losses		0			0
Interest and fees on loans		2,600		$ 1,300	6,500		$ 2,300
Commercial [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans		1,222,802			$ 1,222,802
Total loans	[1]							1,242,415
Percentage of total loans, COVID-19 Accommodations					0.00%
Allowance for credit losses		9,876			$ 9,876				7,922
Mortgage [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans	[2]	1,100,992			$ 1,100,992
Total loans	[1]							1,015,926
Percentage of total loans, COVID-19 Accommodations					0.50%
Allowance for credit losses		19,175			$ 19,175				8,216
Installment [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans	[2]	560,184			$ 560,184
Total loans	[1]							475,337
Percentage of total loans, COVID-19 Accommodations					0.00%
Allowance for credit losses		4,061			$ 4,061				$ 1,283
Mortgage Loans Serviced for Others [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans	[3]	3,237,251			$ 3,237,251
Percentage of total loans, COVID-19 Accommodations	[3]				0.20%
COVID-19 Accommodations [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan					46
Non-TDR loan modifications, portfolio loans outstanding		6,010			$ 6,010
COVID-19 Accommodations [Member] | Commercial [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan					0
Non-TDR loan modifications, portfolio loans outstanding		0			$ 0
COVID-19 Accommodations [Member] | Mortgage [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan					39
Non-TDR loan modifications, portfolio loans outstanding		5,901			$ 5,901
COVID-19 Accommodations [Member] | Installment [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan					7
Non-TDR loan modifications, portfolio loans outstanding		109			$ 109
COVID-19 Accommodations [Member] | Mortgage Loans Serviced for Others [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan	[3]				64
Non-TDR loan modifications, portfolio loans outstanding	[3]	7,986			$ 7,986
COVID-19 Subsequent Accommodation [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan	[4]				41
Non-TDR loan modifications, portfolio loans outstanding	[4]	4,424			$ 4,424
COVID-19 Subsequent Accommodation [Member] | Commercial [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan	[4]				0
Non-TDR loan modifications, portfolio loans outstanding	[4]	0			$ 0
COVID-19 Subsequent Accommodation [Member] | Mortgage [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan	[4]				34
Non-TDR loan modifications, portfolio loans outstanding	[4]	4,315			$ 4,315
COVID-19 Subsequent Accommodation [Member] | Installment [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Number of loans with Covid 19 Accommodations | Loan	[4]				7
Non-TDR loan modifications, portfolio loans outstanding	[4]	109			$ 109
Closed and Outstanding - Round 1 Loans [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans		$ 1,262			$ 1,262
Total loans								$ 169,782
Number of outstanding loans | Loan		20			20			1,483
Closed and Outstanding - Round 2 Loans [Member] | Paycheck Protection Program [Member]
Non-TDR Loan Modifications and Paycheck Protection Program ("PPP") due to COVID-19 [Abstract]
Total loans		$ 88,888			$ 88,888
Total loans								$ 0
Number of outstanding loans | Loan		806			806			0

[1] Beginning January 1, 2021, calculation is based on CECL methodology. Prior to January 1, 2021, calculation was based on the probable incurred loss methodology.

[2] Credit scores have been updated within the last twelve months.

[3] We have delegated authority from all investors to grant these deferrals on their behalf.

[4] Subsequent accommodations are extensions of the original accommodations that were given as summarized in the paragraph above.