Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 308,121		$ 265,007
Contract with customer, liability	$ 600	$ 1,700
Revenue, performance obligation, description of timing	one year
Insurance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	$ 3,800		4,000
Wealth Management
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	$ 1,900		$ 1,900
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings		$ 1,800