INCOME TAXES (Details) (USD $)	3 Months Ended		12 Months Ended
	Jun. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Income before income taxes
United States			$ 17,033,000	$ 65,851,000	$ 110,189,000
Foreign			65,894,000	71,317,000	42,830,000
Income before income taxes			82,927,000	137,168,000	153,019,000
Current:
Federal			(3,663,000)	30,061,000	35,556,000
State			334,000	368,000	310,000
Foreign			30,950,000	44,749,000	17,273,000
Total current income tax expenses			27,621,000	75,178,000	53,139,000
Deferred and others:
Federal			(4,122,000)	(4,341,000)	77,000
State			(26,000)	(27,000)
Foreign			(4,018,000)	(7,051,000)	1,494,000
Total deferred and other income tax expenses			(8,166,000)	(11,419,000)	1,571,000
Total income tax expenses			19,455,000	63,759,000	54,710,000
Differences between provision for income taxes and income tax expense computed by applying federal rates
Total expense computed by applying federal rates			29,024,000	48,009,000	53,557,000
State and provincial income taxes, net of federal benefit			334,000	368,000	310,000
Adjustments of valuation allowance					(1,007,000)
Excess depletion			(1,114,000)	(1,395,000)	(1,416,000)
Estimates for uncertain tax positions			(7,386,000)	1,868,000	551,000
Statutory tax attributable to non-controlling interest			(293,000)	(1,236,000)	(2,042,000)
Effect of foreign earnings			1,141,000	4,223,000	511,000
Effect of foreign earnings indefinitely reinvested			(1,700,000)
Effect of recognized loss on available-for-sale securities			562,000	4,239,000
Unrealized foreign exchange gains			(367,000)	1,146,000	(546,000)
Changes in estimates and corrected errors of prior year tax			(594,000)	4,979,000	1,075,000
Other			(152,000)	1,558,000	3,717,000
Total income tax expenses			19,455,000	63,759,000	54,710,000
Income tax (benefit) expense resulting from continued review of prior year's tax accounts	(2,600,000)	1,700,000
Deferred tax assets:
Stock-based compensation	3,511,000		3,511,000	3,853,000
Net operating losses	19,322,000		19,322,000	25,943,000
Other deferred tax assets	7,068,000		7,068,000	4,460,000
Total deferred tax assets	29,901,000		29,901,000	34,256,000
Valuation allowance	(4,933,000)		(4,933,000)	(4,606,000)
Net deferred tax assets	24,968,000		24,968,000	29,650,000
Deferred tax liabilities:
Mineral property basis	(158,301,000)		(158,301,000)	(165,936,000)
Unrealized foreign exchange gains	(3,072,000)		(3,072,000)	(3,684,000)
2019 Notes	(20,002,000)		(20,002,000)	(23,281,000)
Other deferred tax liabilities	(2,239,000)		(2,239,000)	(3,561,000)
Total deferred tax liabilities	(183,614,000)		(183,614,000)	(196,462,000)
Total net deferred taxes	(158,646,000)		(158,646,000)	(166,812,000)
Net operating loss carry forwards
Net operating loss carry forwards	77,000,000		77,000,000	108,000,000
Reconciliation of beginning and ending amount of gross unrecognized tax benefits
Total gross unrecognized tax benefits at beginning of year		21,166,000	21,166,000	19,469,000	18,836,000
Additions / Reductions for tax positions of current year			(1,052,000)	2,638,000	2,051,000
Reductions due to settlements with taxing authorities			(296,000)	(941,000)
Reductions due to lapse of statute of limitations			(6,093,000)		(1,418,000)
Total amount of gross unrecognized tax benefits at end of year	13,725,000		13,725,000	21,166,000	19,469,000
Net unrecognized tax benefits
Expiration period of statute of limitations for income tax examinations			12 months
Accrued income-tax-related interest and penalties	$ 5,400,000		$ 5,400,000	$ 4,300,000