Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

Financial Instruments (Details) (USD $)	Apr. 25, 2012	Jan. 30, 2012 Five year senior unsecured revolving credit agreement [Member]	Mar. 31, 2012 Publicly Traded Debt [Member]	Mar. 31, 2011 Publicly Traded Debt [Member]	Mar. 31, 2012 Non-Traded Debt [Member]	Mar. 31, 2011 Non-Traded Debt [Member]
Financial Instruments
Carrying Amount			$ 632,435,000	$ 632,387,000	$ 12,356,000	$ 28,509,000
Fair Value			701,156,000	666,247,000	11,860,000	26,720,000
Financial Instruments (Textual) [Abstract]
New credit agreements	$ 150,000,000	$ 500,000,000