For an unclassified balance sheet, the accumulated amortization, as of the reporting date, representing the periodic charge to earnings of deferred costs which are associated with debt obligations existing as of the end of the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

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

Significant Accounting Policies (Details 3) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2007 Interest Rate Swap
Deferred Financing Costs
Accumulated amortization of deferred financing costs	$ 12.3	$ 8.6
Derivative Financial Instrument
Amount of interest rate swap agreements			$ 230.0