Goodwill and Other Intangible Assets - Summary of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross  Carrying Amount	$ 84,962	$ 84,962
Accumulated Amortization	(54,823)	(47,702)
Net Carrying Amount	30,139	37,260
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Gross  Carrying Amount	82,492	82,492
Accumulated Amortization	(53,539)	(46,599)
Net Carrying Amount	28,953	35,893
Customer relationship intangible
Finite-Lived Intangible Assets [Line Items]
Gross  Carrying Amount	2,470	2,470
Accumulated Amortization	(1,284)	(1,103)
Net Carrying Amount	$ 1,186	$ 1,367