Segment Reporting, Reconciliation of Segment Earnings to Earnings Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reconciliation of Segment Earnings [Abstract]
General and administrative	$ (2,637)	$ (2,200)
Operating (loss) earnings	(1,584)	2,339
Interest income	159	103
Interest expense	(1)	0
Loss (earnings) before income taxes and equity investments	(1,426)	2,442
Reportable Segments [Member]
Reconciliation of Segment Earnings [Abstract]
Segment operating earnings	1,053	4,539
Segment Reconciling Item [Member]
Reconciliation of Segment Earnings [Abstract]
General and administrative	(2,637)	(2,200)
Interest income	159	103
Interest expense	$ (1)	$ 0