Debt (Outstanding Debt Including Capital Leases) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Capital lease and lease financing obligations	$ 53,023	$ 13,062
Total debt and lease obligations	820,937	637,229
Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding debt	400,000	239,838
Senior Notes Net of Discount [Member]
Debt Instrument [Line Items]
Outstanding debt	297,914	297,729
Richmond Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding debt	$ 70,000	70,000
Atlanta-Metro Equipment Loan [Member]
Debt Instrument [Line Items]
Outstanding debt		$ 16,600

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 30

-Section 50

-Paragraph 1

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-Publisher SEC

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-Section 03

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- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

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Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

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 210.5-02.22)

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

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-Publisher SEC

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