Fair Value of Financial Instruments (Details) (USD $) In Millions	Jun. 30, 2011
Fair Value Of Financial Instruments (Textuals) [Abstract]
Fair value of fixed rate debt	$ 522.0

Estimated fair value of the debt instrument at the balance-sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant