EMPLOYEE BENEFIT PLANS (Details)	3 Months Ended		9 Months Ended			9 Months Ended		9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2014 Chief Executive Officer [Member] USD ($)	Dec. 31, 2014 Plan 2007 [Member]	Dec. 31, 2014 UK Pension Plans [Member] USD ($)	Mar. 31, 2015 UK Pension Plans [Member] Forecast [Member] USD ($)	Dec. 31, 2014 Norway pension plan [Member] USD ($)	Mar. 31, 2015 Norway pension plan [Member] Forecast [Member] USD ($)	Mar. 31, 2014 UK staff pension plan [Member] USD ($)	Mar. 31, 2014 UK staff pension plan [Member] GBP (£)
Pension Plan [Line Items]
Service cost	$ 1,897,000	$ 2,162,000	$ 6,230,000	$ 6,283,000
Interest cost	5,852,000	6,892,000	19,218,000	20,032,000
Expected return on assets	(6,945,000)	(7,486,000)	(22,806,000)	(21,759,000)
Amortization of unrecognized losses	1,493,000	1,978,000	4,902,000	5,752,000
Net periodic pension cost	2,297,000	3,546,000	7,544,000	10,308,000
Cash Contributions								15,100,000		9,000,000		20,800,000	12,500,000
Estimated cash contributions									21,200,000		12,000,000
Incentive Compensation [Line Items]
Common Stock Shares reserved							5,400,000
Common stock, par value	$ 0.01		$ 0.01		$ 0.01
Shares available for grant							2,355,553
Stock based compensation expense	5,300,000	4,000,000	13,651,000	10,694,000
Stock option grants- shares			472,744
Restricted stock grants- shares			172,808
Restricted stock grants- fair value			$ 74.18
Risk free interest rate			1.67%
Expected life (years)			5 years
Volatility			34.20%
Dividend yield			1.92%
Weighted average exercise price of options granted			$ 74.44
Weighted average grant-date fair value of options granted			$ 17.17
Performance cash compensation liability	17,800,000		17,800,000		16,700,000
Performance cash compensation expense	4,300,000	2,400,000	11,300,000	6,100,000
Compensation						$ 5,500,000