Basis of Presentation and Significant Accounting Policies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) segment portfolio_segment	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jan. 01, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of operating segments | segment	2
Expected credit losses, number of loan pools calculated using the discounted cash flow method | portfolio_segment	8
Number of loan pools | portfolio_segment	11
Expected credit losses, percentage of amortized cost basis of total loans calculated using the discounted cash flow method	96.00%
Expected credit losses, number of loan pools calculated using the weighted average remaining life method | portfolio_segment	3
Increase in retained earnings	$ 242,474	$ 237,218	$ 231,452		$ 221,575	$ 214,616	$ 206,923	$ 197,723	$ 207,117
Decrease in ACL on loans	(13,816)	(14,539)			(21,136)	(21,683)	(20,653)		(19,088)
Assets	2,609,946				2,121,798
Commercial loans	1,450,657				1,444,050
Junior subordinated debentures	10,310				10,310
Derivative notional amount	224,000				196,000
LIBOR
Schedule of Equity Method Investments [Line Items]
Assets	191,800
Commercial loans	119,500
Debt securities	72,300
Junior subordinated debentures	10,000
Derivative notional amount	154,800
LIBOR | Interest rate swaps | Subordinated debt
Schedule of Equity Method Investments [Line Items]
Derivative notional amount	10,000
LIBOR | Interest rate swaps | Commercial banking customers
Schedule of Equity Method Investments [Line Items]
Derivative notional amount	72,400
LIBOR | Interest rate swaps | Third party financial institutions
Schedule of Equity Method Investments [Line Items]
Derivative notional amount	72,400
LIBOR | Interest rate swaps | Third party institutions
Schedule of Equity Method Investments [Line Items]
Derivative notional amount	82,400
Purchased Receivables
Schedule of Equity Method Investments [Line Items]
Decrease in ACL on purchased receivables	0	0		$ 0	(73)	(87)	(93)		(94)
Retained Earnings
Schedule of Equity Method Investments [Line Items]
Increase in retained earnings	$ 198,284	$ 191,791	$ 185,766		173,498	$ 165,606	$ 155,998	$ 148,286	149,615
Cumulative effect of adoption of accounting principles
Schedule of Equity Method Investments [Line Items]
Increase in retained earnings					2,400				0
Decrease in ACL on loans				4,500	4,511
Increase in ACL on unfunded commitments				1,200
Decrease in deferred tax assets				954
Cumulative effect of adoption of accounting principles | Purchased Receivables
Schedule of Equity Method Investments [Line Items]
Decrease in ACL on purchased receivables				73
Cumulative effect of adoption of accounting principles |  Retained Earnings
Schedule of Equity Method Investments [Line Items]
Increase in retained earnings				$ 2,400	$ 2,400				$ (139)