INCOME TAXES - Reconciliation (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Differences between provision for income taxes and income tax expense computed by applying federal rates
Total expense computed by applying federal rates		$ (29,343)	$ 41,603	$ (7,615)
State and provincial income taxes, net of federal benefit		(104)	78	(1)
Excess depletion		(1,440)	(1,517)	(882)
Estimates for uncertain tax positions		8,574	2,870	1,866
Statutory tax attributable to non-controlling interest		1,736	3,162	1,838
Effect of foreign earnings		1,230	3,046	61,576
Effect of foreign earnings indefinitely reinvested		(19,004)	(22,922)	3,406
Realized foreign exchange gains		18,330
Unrealized foreign exchange gains		(1,610)	(746)	(2,439)
Effects of US income tax reform		30,675
Changes in estimates		(70)	(3,676)	1,641
Valuation allowance		6,337	4,374	849
Other		(539)	169	441
Total income tax expenses		$ 14,772	$ 26,441	$ 60,680
US corporate income tax rate (as a percent)	21.00%
Effective tax rate (as a percent)		28.10%
Net reduction in income tax expense due to Tax Cuts and Jobs Act		$ 30,700
Mandatory transition tax due to tax legislation		$ 12,300
Mandatory transition tax payment period		8 years
Re-measurement of net deferred tax assets and liabilities due to tax legislation		$ 1,200
Re-measurement of foreign uncertain tax positions due to tax legislation		$ 17,200