Share Based Awards (Details 2) (USD $)	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Summary of stock options granted
Number of Share Granted	459,400	110,000	578,968
Two Thousand Five Stock Options Plan [Member]
Summary of stock options granted
Number of Share Granted	459,400	110,000	578,968
Two Thousand Five Stock Options Plan [Member] | May 31, 2011[Member]
Summary of stock options granted
Option Grant Date	May 31, 2011
Number of Share Granted	459,400
Exercise Price Granted	43.04
Exercise of option grants	Five Years
Option Grants Expires	43616
Two Thousand Five Stock Options Plan [Member] | Fiscal year 2012 option grants [Member]
Summary of stock options granted
Number of Share Granted	459,400
Two Thousand Five Stock Options Plan [Member] | November 29, 2010 [Member]
Summary of stock options granted
Option Grant Date		Nov. 29, 2010
Number of Share Granted		20,000
Exercise Price Granted		32.16
Exercise of option grants		Five Years
Option Grants Expires		43433
Two Thousand Five Stock Options Plan [Member] | August 3, 2010 [Member]
Summary of stock options granted
Option Grant Date		Aug. 03, 2010
Number of Share Granted		10,000
Exercise Price Granted		27.62
Exercise of option grants		Five Years
Option Grants Expires		43315
Two Thousand Five Stock Options Plan [Member] | June 4, 2010 [Member]
Summary of stock options granted
Option Grant Date		Jun. 04, 2010
Number of Share Granted		50,000
Exercise Price Granted		28.15
Exercise of option grants		Five Years
Option Grants Expires		43255
Two Thousand Five Stock Options Plan [Member] | June 2, 2010 [Member]
Summary of stock options granted
Option Grant Date		Jun. 02, 2010
Number of Share Granted		30,000
Exercise Price Granted		29.31
Exercise of option grants		Five Years
Option Grants Expires		43253
Two Thousand Five Stock Options Plan [Member] | Fiscal year 2011 option grants [Member]
Summary of stock options granted
Number of Share Granted		110,000
Two Thousand Five Stock Options Plan [Member] | February 16, 2010 [Member]
Summary of stock options granted
Option Grant Date			Feb. 16, 2010
Number of Share Granted			236,118
Exercise Price Granted			28.48
Exercise of option grants			Five years
Option Grants Expires			43147
Two Thousand Five Stock Options Plan [Member] | February 16, 2010 [Member]
Summary of stock options granted
Option Grant Date			Feb. 16, 2010
Number of Share Granted			6,000
Exercise Price Granted			28.48
Exercise of option grants			Two years
Option Grants Expires			41321
Two Thousand Five Stock Options Plan [Member] | December 7, 2009 [Member]
Summary of stock options granted
Option Grant Date			Dec. 07, 2009
Number of Share Granted			126,850
Exercise Price Granted			30.15
Exercise of option grants			Five years
Option Grants Expires			43076
Two Thousand Five Stock Options Plan [Member] | November 30, 2009 [Member]
Summary of stock options granted
Option Grant Date			Nov. 30, 2009
Number of Share Granted			150,000
Exercise Price Granted			29.75
Exercise of option grants			Five years
Option Grants Expires			43069
Two Thousand Five Stock Options Plan [Member] | September 17, 2009 [Member]
Summary of stock options granted
Option Grant Date			Sep. 17, 2009
Number of Share Granted			60,000
Exercise Price Granted			29.02
Exercise of option grants			Five years
Option Grants Expires			42995
Two Thousand Five Stock Options Plan [Member] | Fiscal year 2011 option grants [Member]
Summary of stock options granted
Number of Share Granted			578,968