Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases
Operating lease ROU assets	$ 23,457	$ 36,800
Financial position	us-gaap:OtherAssetsNoncurrent
Operating lease liabilities - current	$ 10,479
Financial position	us-gaap:OtherLiabilitiesCurrent
Operating lease liabilities - noncurrent	$ 14,694
Financial position	us-gaap:OtherLiabilitiesNoncurrent
Total Operating lease liabilities	$ 25,173	$ 36,800
Property and equipment, gross	174,960		$ 202,698
Accumulated depreciation	(140,234)		$ (139,269)
Financing Lease ROU assets	$ 248
Financial position	Property, Plant and Equipment, Net
Finance lease liabilities - current	$ 203
Financial position	us-gaap:OtherLiabilitiesCurrent
Finance lease liabilities - noncurrent	$ 55
Financial position	us-gaap:OtherLiabilitiesNoncurrent
Finance lease liabilities	$ 258
Weighted average remaining lease term - Operating leases	4 years
Weighted average remaining lease term - Financing leases	1 year
Weighted average discount rate - Operating leases	4.32%
Weighted average discount rate - Financing leases	6.00%
Finance lease assets
Leases
Property and equipment, gross	$ 985
Accumulated depreciation	$ (737)