Goodwill and Other Intangible Assets - Current Year Amortization Expense for Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 1,733	$ 1,996	$ 5,462	$ 6,159
Core deposit intangibles
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	1,688	1,963	5,326	6,060
Customer relationship intangible
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 45	$ 33	$ 136	$ 99