CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
General and administrative expense	$ 2,262	$ 3,516	$ 7,922	$ 14,253
Operating loss	(2,262)	(3,516)	(7,922)	(14,253)
Other income (loss), net	8,777	(1,078)	10,010	(4,965)
Interest income	234	718	1,870	2,182
Interest expense	(5,806)	(3,310)	(14,023)	(9,422)
Equity income (loss), net	(3,440)	39,246	65,324	27,452
Net income (loss) before income taxes	(2,497)	32,060	55,259	994
Income tax benefit (expense)	0	0	0	0
Net income (loss)	$ (2,497)	$ 32,060	$ 55,259	$ 994
Net income (loss) per share:
Basic (in dollars per share)	$ (0.12)	$ 1.56	$ 2.68	$ 0.05
Diluted (in dollars per share)	$ (0.12)	$ 1.56	$ 2.68	$ 0.05
Weighted average shares used in computing income (loss) per share:
Basic (in shares)	20,657	20,561	20,623	20,535
Diluted (in shares)	20,657	20,561	20,623	20,535