Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Total Revenue	$ 159,633	$ 171,797
COSTS AND EXPENSES
Costs applicable to sales	106,896	88,059	[1]
Amortization	40,459	49,724
General and administrative	13,896	10,227
Exploration	4,217	6,841
Write-downs	0	119
Pre-development, reclamation, and other	6,984	5,197
Total cost and expenses	172,452	160,167
OTHER INCOME AND EXPENSE
Fair value adjustments, net	(11,436)	17,796
Impairment of marketable securities	(2,588)	(35)
Interest and other income	(1,983)	3,856
Interest expense, net of capitalized interest	(13,054)	(9,732)
Total other income and expense	(29,061)	11,885
Income before income taxes	(41,880)	23,515
Income tax benefit (expense)	4,689	(11,245)
NET INCOME (LOSS)	(37,191)	12,270
Other Comprehensive Income (Loss), Net of Tax:
Unrealized gain (loss) on available for sale securities	371	(3,566)
Reclassification adjustments for other than temporary impairment of marketable securities	1,587	35
Other comprehensive income (loss)	1,958	(3,531)
COMPREHENSIVE INCOME	$ (35,233)	$ 8,739
BASIC AND DILUTED INCOME PER SHARE
Basic (in dollars per share)	$ (0.36)	$ 0.14
Diluted (in dollars per share)	$ (0.36)	$ 0.14

[1] Excludes amortization.