Benefit Plans (Details) (USD $)			3 Months Ended	9 Months Ended
Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2011 Withdrawal from Multiemployer Defined Benefit Plan [Member]	Dec. 31, 2010 Withdrawal from Multiemployer Defined Benefit Plan [Member]	Dec. 31, 2011 Withdrawal from Multiemployer Defined Benefit Plan [Member]	Dec. 31, 2010 Withdrawal from Multiemployer Defined Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Charges related to the withdrawal from multi-employer pension plans			$ 3,400,000	$ 0	$ 4,300,000	$ 4,600,000
Withdrawal liabilities	$ 1,600,000	$ 16,000,000

Amount of a recognized obligation to a multiemployer plan in the event that the employer withdraws from the plan. In some situations, withdrawal from a multiemployer plan may result in an employer having an obligation to the plan for a portion of the unfunded benefit obligation of the pension plans and other postretirement benefit plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_MultiemployerPlanWithdrawalObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant