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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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

Long-Term Debt (Narrative) (Details) (USD $)	0 Months Ended		12 Months Ended
Long-Term Debt (Narrative) (Details) (USD $)	Jul. 08, 2011 Senior Credit Facility [Member]	Jan. 20, 2012 Incremental Senior Credit Facility [Member]	Dec. 31, 2012 Incremental Senior Credit Facility [Member]	Dec. 31, 2012 Incremental Senior Credit Facility [Member] Eight Scheduled Quarterly [Member]	Dec. 31, 2012 Incremental Senior Credit Facility [Member] Four Scheduled Quarterly [Member]
Debt Instrument [Line Items]
Term of line of credit (years)	5 years
Maximum borrowing capacity under credit facility	$ 900,000,000	$ 150,000,000
Payment of financing costs	8,285,000	1,018,000
Unamortized financing costs	12,277,000
Periodic payment, principal			$ 5,625,000	$ 1,875,000	$ 3,750,000