EMPLOYEE BENEFIT PLANS (Details) (USD $)	3 Months Ended				12 Months Ended	3 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013	Jun. 30, 2013 Plan 2007 [Member]	Mar. 31, 2013 UK staff pension plan [Member]	Jun. 30, 2013 UK expatriate pension plan [Member]	Mar. 31, 2013 UK expatriate pension plan [Member]	Jun. 30, 2013 Norway pension plan [Member]	Mar. 31, 2013 Norway pension plan [Member]
Pension Plan [Line Items]
Service cost	$ 2,051,000	$ 2,057,000
Interest cost	6,538,000	6,433,000
Expected return on assets	(7,102,000)	(7,281,000)
Amortization of unrecognized losses	1,877,000	1,657,000
Net periodic pension cost	3,364,000	2,866,000
Cash Contributions					19,000,000	100,000		2,700,000
Estimated cash contributions							300,000		8,100,000
Incentive Compensation [Line Items]
Common Stock Shares reserved				5,400,000
Shares available for grant				3,013,210
Stock based compensation expense	2,869,000	2,848,000
Stock option grants- shares	302,678
Restricted stock grants- shares	163,396
Restricted stock grants- fair value	$ 62.66
Risk free interest rate	1.01%
Expected life (years)	5 years
Volatility	48.70%
Dividend yield	1.60%
Weighted average exercise price of options granted	$ 62.66
Weighted average grant-date fair value of options granted	$ 23.77
Performance cash compensation liability	10,200,000		13,400,000
Performance cash compensation expense	$ 1,800,000	$ 900,000