RESTRUCTURING, IMPAIRMENT AND OTHER CHARGES: - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	$ 6,396	$ 6,740	$ 11,632
Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	6,400
Fiscal 2017 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		8,900
Fiscal 2016 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			12,000
Fiscal 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				$ 21,800
Severance and Other Associate-Related | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	3,800
Severance and Other Associate-Related | Fiscal 2017 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		3,800
Severance and Other Associate-Related | Fiscal 2016 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			8,600
Severance and Other Associate-Related | Fiscal 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				13,300
Leasehold Improvement Write Offs | Fiscal 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		2,100
Leasehold Improvement Write Offs | Fiscal 2016 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			400
Leasehold Improvement Write Offs | Fiscal 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				2,000
Other Associate-Related Charges
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	2,200
Lease Accruals And Adjustments | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	2,600
Lease Accruals | Fiscal 2017 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		3,000
Lease Accruals | Fiscal 2016 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			3,000
Lease Accruals | Fiscal 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				6,500
Leased Office Facilities | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		1,500
Adjustments To Estimates Related To Lease Accruals | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		1,500
Facility Lease Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	12,100
Facility Lease Restructuring Charges | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	5,300
FRANCE | Fiscal 2017 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		$ 3,000
FRANCE | Fiscal 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			3,000
United States Europe And Australia | Severance and Other Associate-Related | Fiscal 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	3,800
United States Australia Europe And Brazil | Severance and Other Associate-Related
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	200
United States Australia Europe And Brazil | Severance and Other Associate-Related | Fiscal 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			$ 8,600
United States Australia China And Europe | Severance and Other Associate-Related | Fiscal 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				$ 13,300
Restructuring reserve	$ 300