Long-term Debt (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2012
Line of Credit Facility [Line Items]
Payments of debt issuance costs		$ 0
Description of rate basis	three-month LIBOR	three-month LIBOR
Wells Fargo Capital Finance, LLC and certain other lenders [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	100,000,000	100,000,000
Payments of debt issuance costs		$ 1,700,000
Interest rate percent above LIBOR (percentage)	1.00%	1.00%
LIBOR-based loans initial applicable margin (percentage)	2.00%
Base Rate loans initial applicable margin (percentage)	1.00%

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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