INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Income before income taxes
United States	$ 15,253	$ (230)	$ 17,569
Foreign	103,613	(21,528)	44,675
Income (loss) before income taxes	118,866	(21,758)	62,244
Current:
Federal	13,975	45,878	22,418
State	308	135	(36)
Foreign	10,602	19,650	14,835
Total current income tax expenses	24,885	65,663	37,217
Deferred and others:
Federal	(1,443)	(6,986)	(5,506)
State	(18)	(78)	(49)
Foreign	3,017	2,081	(22,096)
Total deferred and other income tax expenses	1,556	(4,983)	(27,651)
Total income tax expenses	26,441	60,680	9,566
Differences between provision for income taxes and income tax expense computed by applying federal rates
Total expense computed by applying federal rates	41,603	(7,615)	21,786
State and provincial income taxes, net of federal benefit	78	(1)	25
Excess depletion	(1,517)	(882)	(1,429)
Estimates for uncertain tax positions	2,870	1,866	1,404
Statutory tax attributable to non-controlling interest	3,162	1,838	(211)
Effect of foreign earnings	3,046	61,576	6,536
Effect of foreign earnings indefinitely reinvested	(22,922)	3,406	(7,601)
Unrealized foreign exchange gains	(746)	(2,439)	(10,949)
Changes in estimates	(3,676)	1,641	(359)
Valuation allowance	4,374	849
Other	169	441	(1,225)
Total income tax expenses	26,441	60,680	9,566
Deferred tax assets:
Stock-based compensation	5,979	5,691
Net operating losses	5,341	12,385
Foreign tax credits	19,869
Other	7,382	4,610
Total deferred tax assets	38,571	22,686
Valuation allowance	(6,474)	(2,100)
Net deferred tax assets	32,097	20,586
Deferred tax liabilities:
Mineral property basis	(122,870)	(127,337)
Unrealized foreign exchange gains	(1,097)	(1,273)
2019 Notes	(8,634)	(12,639)
Investment in the Peak Gold JV	(5,475)
Other	(595)	(124)
Total deferred tax liabilities	(138,671)	(141,373)
Total net deferred taxes	(106,574)	(120,787)
Net operating loss carry forwards	$ 32,100	59,500
Tax carryforward period	20 years
Reconciliation of beginning and ending amount of gross unrecognized tax benefits
Total gross unrecognized tax benefits at beginning of year	$ 26,960	26,120	23,956
Additions / Reductions for tax positions of current year	1,394	840	2,421
Additions / Reductions for tax positions of prior years	188
Reductions due to settlements with taxing authorities			(257)
Total amount of gross unrecognized tax benefits at end of year	28,542	26,960	26,120
Accrued income-tax-related interest and penalties	6,800	$ 5,700
Advanced deposits	$ 9,700
Canada
Differences between provision for income taxes and income tax expense computed by applying federal rates
Income tax rate adjustment/ reform			4,070
Chile
Differences between provision for income taxes and income tax expense computed by applying federal rates
Income tax rate adjustment/ reform			$ (2,481)