Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Financial Instruments at Fair Value Disclosure (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014
Assets and Liabilities, at Fair Value [Abstract]
Long-term Debt, Fair Value		$ 47.8us-gaap_LongTermDebtFairValue
Senior unsecured notes	$ 45.5us-gaap_SeniorNotes	$ 45.5us-gaap_SeniorNotes	$ 45.5us-gaap_SeniorNotes

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16(a))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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