Revenue from Contracts with Customers - Disaggregation of Revenue by Source (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 38,722	$ 34,415	$ 114,313	$ 102,224
Mortgage broker fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	295	412	862	1,142
Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	9,331	8,645	27,339	25,606
Administrative services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,099	1,052	3,365	3,062
Card related fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,328	1,471	5,583	4,315
Other deposit related fees
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,035	3,032	8,927	8,243
Wealth management
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	22,634	19,803	68,237	59,856
Wealth management | Brokerage and insurance product commissions
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,579	5,127	17,394	16,796
Wealth management | Trust
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,003	2,932	9,646	9,477
Wealth management | Asset management
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 14,052	$ 11,744	$ 41,197	$ 33,583