- Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	$ 1,981	$ 1,856	$ 2,613
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	6	84	389
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	292	287	168
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	1,527	954	734
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	52	408	1,211
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	$ 104	$ 123	$ 111