Leases - Rental Expense, Net of Sublease Income presented in accordance with Topic 840 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Rental expense, net of sublease income, presented in accordance with Topic 840
Net rental expense	$ 12,723	$ 7,563
Occupancy
Rental expense, net of sublease income, presented in accordance with Topic 840
Rental expense charged to occupancy	9,947	8,620
Less: Sublease income	903	1,342
Net rental expense	9,044	7,278
Equipment
Rental expense, net of sublease income, presented in accordance with Topic 840
Rental expense charged to equipment expense	$ 3,679	$ 285