Goodwill and Other Intangible Assets - Summary of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 84,962	$ 84,462
Accumulated Amortization	(47,702)	(39,597)
Net Carrying Amount	37,260	44,865
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	82,492	82,492
Accumulated Amortization	(46,599)	(38,634)
Net Carrying Amount	35,893	43,858
Customer relationship intangible
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,470	1,970
Accumulated Amortization	(1,103)	(963)
Net Carrying Amount	$ 1,367	$ 1,007