SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advance Royalties and Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Advance Royalties
Allowance against royalty prepayments	$ 3,800	$ 1,300
Advance royalties, affiliates (see Note 19 - Related Party Transactions)	16,245	10,706
Advance royalties, third-parties	11,870	14,605
Total advance royalties, net	$ 28,115	$ 25,311
Income Taxes
Percentage of qualifying income for tax purposes	90.00%