Leases - Future Minimum Rental Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Future minimum lease payments under non-cancelable operating leases
One year	$ 5,140
Two years	4,730
Three years	2,000
Four years	902
Five years	482
Thereafter	610
Total lease payments	13,864
Less landlord paid tenant improvements	(597)
Less imputed interest	(1,419)
Total	$ 11,848	$ 11,900