Non-Interest Revenues - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, liability	$ 3,118		$ 3,118		$ 2,001
Contract with customer, asset	2,500		2,500		$ 1,100
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,200	$ 1,300	$ 2,700	$ 3,200