Benefit Plans (MEPPs) (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Charges related to the withdrawal from multi-employer pension plans	$ 0	$ 3,404,000	$ 0	$ 900,000	$ 0	$ 4,300,000	$ 4,600,000
Multi-Employer Plan Withdrawal Liabilities	$ 1,600,000				$ 900,000	$ 1,600,000

Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

No definition available.

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