Segment Reporting, Reconciliation of Segment Earnings to Earnings Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	$ 619	$ 5,601	$ (965)	$ 7,940
Loss on deconsolidation of subsidiary	(1,635)	0	(1,635)	0
Losses from equity investments	0	(209)	0	(400)
Interest income	260	96	419	199
Interest expense	(1)	0	(2)	0
(Losses) earnings before income taxes	(757)	5,488	(2,183)	7,739
Reportable segments
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	2,079	7,539	3,132	12,078
Corporate non-segment
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	(1,460)	(1,938)	(4,097)	(4,138)
Segment reconciling items
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Interest income	260	96	419	199
Interest expense	$ (1)	$ 0	$ (2)	$ 0