Allowance for Credit Losses - Reserve for Unfunded Commitments (Details) - Reserve for unfunded commitments - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	$ 34,103	$ 17,251	$ 30,603	$ 600
Increase (decrease) in Provision	(4,881)	5,953	(1,381)	6,304
Reserve for unfunded commitments, ending balance	29,222	23,204	29,222	23,204
Commercial and Industrial
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	16,129	4,791	11,719
Increase (decrease) in Provision	(3,321)	3,390	1,089	2,791
Reserve for unfunded commitments, ending balance	12,808	8,181	12,808	8,181
Commercial Real Estate
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	1,112	696	1,328
Increase (decrease) in Provision	(134)	472	(350)	390
Reserve for unfunded commitments, ending balance	978	1,168	978	1,168
Construction
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	8,313	4,813	9,037
Increase (decrease) in Provision	(440)	1,095	(1,164)	1,789
Reserve for unfunded commitments, ending balance	7,873	5,908	7,873	5,908
Residential mortgage
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance		1	2
Increase (decrease) in Provision		2	(2)	(4)
Reserve for unfunded commitments, ending balance		3		3
Home equity
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	8,500	6,927	8,452
Increase (decrease) in Provision	(979)	963	(931)	1,303
Reserve for unfunded commitments, ending balance	7,521	7,890	7,521	7,890
Consumer
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	49	23	65	600
Increase (decrease) in Provision	(7)	31	(23)	35
Reserve for unfunded commitments, ending balance	$ 42	$ 54	$ 42	54
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				16,300
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Commercial and Industrial
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				5,390
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Commercial Real Estate
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				778
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Construction
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				4,119
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Residential mortgage
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				7
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Home equity
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				6,587
ASU No. 2016-13 | Cumulative-effect adjustment of a change in accounting principle, net of tax: ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments | Consumer
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance				$ (581)