Operating Leases - Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income and Expenses, Lessee [Abstract]
Operating lease, expense	$ 2,227
Operating Leases, Rent Expense, Net [Abstract]
Rent expense		$ 2,257	$ 2,482