EMPLOYEE BENEFIT PLANS (Details) $ / shares in Units, $ in Thousands, £ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 GBP (£)	Mar. 31, 2015 USD ($) $ / shares
Pension Plan [Line Items]
Service cost	$ 2,373	$ 2,246
Interest cost	5,171	6,929
Expected return on assets	(6,941)	(8,223)
Amortization of unrecognized losses	2,131	1,768
Net periodic pension cost	$ 2,734	2,720
Incentive Compensation [Line Items]
Common stock, par value | $ / shares	$ 0.01				$ 0.01
Stock based compensation expense	$ 3,967	4,187
Restricted stock grants- shares | shares	190,439
Restricted stock grants- fair value | $ / shares	$ 58.17
Stock option grants- shares | shares	714,312
Risk free interest rate	1.63%
Expected life (years)	6 years
Volatility	28.10%
Dividend yield	3.14%
Weighted average exercise price of options granted | $ / shares	$ 58.17
Weighted average grant-date fair value of options granted | $ / shares	$ 10.84
Performance cash compensation liability	$ 15,600				$ 21,000
Performance cash compensation expense	$ 3,400	$ 2,100
Plan 2007 [Member]
Incentive Compensation [Line Items]
Common stock shares reserved | shares	5,400,000
Shares available for grant | shares	1,480,493
Pension Plan [Member] | UK staff pension plan [Member]
Pension Plan [Line Items]
Cash Contributions				£ 12.5	$ 18,600
Pension Plan [Member] | Norway pension plan [Member]
Pension Plan [Line Items]
Cash Contributions	$ 2,200
Pension Plan [Member] | Norway pension plan [Member] | Scenario, Forecast [Member]
Pension Plan [Line Items]
Estimated cash contributions			$ 11,700
Pension Plan [Member] | UK Pension Plans [Member]
Pension Plan [Line Items]
Cash Contributions	$ 2,500
Pension Plan [Member] | UK Pension Plans [Member] | Scenario, Forecast [Member]
Pension Plan [Line Items]
Estimated cash contributions			$ 18,100