CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Royalties	$ 2,272	$ 5,097	$ 5,496	$ 10,302
Miscellaneous income	0	95	42	151
Total revenues	2,272	5,192	5,538	10,453
Operating expenses:
General and administrative	436	516	1,157	1,099
Total operating expenses	436	516	1,157	1,099
Operating income and income before income tax expense (benefit)	1,836	4,676	4,381	9,354
Income tax expense (benefit)	801	894	1,829	(1,600)
Net income	$ 1,035	$ 3,782	$ 2,552	$ 10,954
Earnings per common share
Basic	$ 0.02	$ 0.09	$ 0.06	$ 0.25
Diluted	$ 0.02	$ 0.09	$ 0.06	$ 0.25
Weighted-average shares - basic	44,120	44,182	44,167	44,182
Weighted-average shares - diluted	44,120	44,215	44,167	44,228