Leases Lease Related Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Finance lease expense:
Amortization of finance lease assets	$ 261	$ 784
Interest on finance lease liabilities	105	321
Operating lease expense	2,127	6,444
Variable lease expense	143	474
Short-term lease expense	6	28
Sublease income	(158)	(586)
Total lease expense	$ 2,484	$ 7,465