Allowance for Credit Losses - Reserve for Unfunded Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Reserve for unfunded commitments:
Adoption of ASU 2016-13		$ 770
Commercial and Industrial
Reserve for unfunded commitments:
Adoption of ASU 2016-13		(16,105)
Commercial real estate
Reserve for unfunded commitments:
Adoption of ASU 2016-13		10,559
Construction
Reserve for unfunded commitments:
Adoption of ASU 2016-13		(1,803)
Lease financing
Reserve for unfunded commitments:
Adoption of ASU 2016-13		207
Consumer
Reserve for unfunded commitments:
Adoption of ASU 2016-13		15,575
Reserve for unfunded commitments
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	$ 600
Adoption of ASU 2016-13		16,300
Increase (decrease) in Provision	351
Reserve for unfunded commitments, ending balance	17,251
Reserve for unfunded commitments | Commercial and Industrial
Reserve for unfunded commitments:
Adoption of ASU 2016-13		5,390
Increase (decrease) in Provision	(599)
Reserve for unfunded commitments, ending balance	4,791
Reserve for unfunded commitments | Commercial real estate
Reserve for unfunded commitments:
Adoption of ASU 2016-13		778
Increase (decrease) in Provision	(82)
Reserve for unfunded commitments, ending balance	696
Reserve for unfunded commitments | Construction
Reserve for unfunded commitments:
Adoption of ASU 2016-13		4,119
Increase (decrease) in Provision	694
Reserve for unfunded commitments, ending balance	4,813
Reserve for unfunded commitments | Residential mortgage
Reserve for unfunded commitments:
Adoption of ASU 2016-13		7
Increase (decrease) in Provision	(6)
Reserve for unfunded commitments, ending balance	1
Reserve for unfunded commitments | Home equity
Reserve for unfunded commitments:
Adoption of ASU 2016-13		6,587
Increase (decrease) in Provision	340
Reserve for unfunded commitments, ending balance	6,927
Reserve for unfunded commitments | Consumer
Reserve for unfunded commitments:
Reserve for unfunded commitments, beginning balance	600
Adoption of ASU 2016-13		$ (581)
Increase (decrease) in Provision	4
Reserve for unfunded commitments, ending balance	$ 23