EARNINGS PER SHARE AND ACCUMULATED OTHER COMPREHENSIVE INCOME - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Accumulated other comprehensive loss - beginning balance		$ (327,989)			$ (327,989)
Net current period other comprehensive income	$ (11,175)	17,362	$ (8,097)	$ (27,824)
Accumulated other comprehensive loss - ending balance	(321,802)				(321,802)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Accumulated other comprehensive loss - beginning balance		(327,989)			(327,989)
Other comprehensive income before reclassification					7,322
Reclassified from accumulated other comprehensive income					(1,135)
Net current period other comprehensive income					6,187
Foreign exchange rate impact	0				0
Accumulated other comprehensive loss - ending balance	(321,802)				(321,802)
Currency Translation Adjustments | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Accumulated other comprehensive loss - beginning balance		(137,867)			(137,867)
Other comprehensive income before reclassification					4,589
Reclassified from accumulated other comprehensive income					0
Net current period other comprehensive income					4,589
Foreign exchange rate impact	(12,133)				(12,133)
Accumulated other comprehensive loss - ending balance	(145,411)				(145,411)
Pension Liability Adjustments | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Accumulated other comprehensive loss - beginning balance		(189,734)			(189,734)
Other comprehensive income before reclassification					0
Reclassified from accumulated other comprehensive income					0
Net current period other comprehensive income					0
Foreign exchange rate impact	12,133				12,133
Accumulated other comprehensive loss - ending balance	(177,601)				(177,601)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Accumulated other comprehensive loss - beginning balance		$ (388)			(388)
Other comprehensive income before reclassification					2,733
Reclassified from accumulated other comprehensive income					(1,135)
Net current period other comprehensive income					1,598
Foreign exchange rate impact	0				0
Accumulated other comprehensive loss - ending balance	$ 1,210				$ 1,210