Segment Reporting, Reconciliation of Segment Earnings to Earnings Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	$ (1,290)	$ (1,822)	$ (2,255)	$ 6,118
Loss on deconsolidation of subsidiary (Note 3)	(1,870)	0	(3,505)	0
Impairment of investments in unconsolidated affiliates	(2,500)	(1,732)	(2,500)	(1,732)
Losses from equity investment	0	(68)	0	(468)
Interest income	370	245	789	444
Interest expense	(8)	0	(10)	0
(Losses) earnings before income taxes	(5,298)	(3,377)	(7,481)	4,362
Reportable segments
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	1,497	292	4,629	12,370
Corporate non-segment
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating earnings (losses)	(2,787)	(2,114)	(6,884)	(6,252)
Segment reconciling items
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Loss on deconsolidation of subsidiary (Note 3)	(1,870)	0	(3,505)	0
Impairment of investments in unconsolidated affiliates	(2,500)	(1,732)	(2,500)	(1,732)
Losses from equity investment	0	(68)	0	(468)
Interest income	370	245	789	444
Interest expense	$ (8)	$ 0	$ (10)	$ 0