Goodwill and Other Intangible Assets - Current Year Amortization Expense for Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 2,053	$ 1,594	$ 4,163	$ 3,245
Core Deposit Intangibles
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	2,020	1,561	4,097	3,179
Customer Relationship Intangible
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization	$ 33	$ 33	$ 66	$ 66