Goodwill and Other Intangible Assets - Current Year Amortization Expense for Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 1,895	$ 2,110
Core deposit intangibles
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	1,850	2,077
Customer relationship intangible
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 45	$ 33