Premises and Equipment - Lease Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Finance lease, ROU assets	$ 5,999	$ 6,537
Finance lease, accumulated depreciation	(273)	(917)
Finance lease, net ROU assets	5,726	5,620
Finance lease, lease liabilities	$ 5,891	$ 5,671
Finance lease, weighted-average remaining lease term	24 years	24 years
Finance lease, weighted-average discount rate	2.60%	3.00%
Operating lease, net ROU assets	$ 46,820	$ 41,453
Operating lease, lease liabilities	$ 49,675	$ 43,904
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Operating lease, weighted-average remaining lease term (in years)	17 years	19 years
Operating lease, weighted-average discount rate	3.40%	3.70%