Debt - Schedule of Debt Principal Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Long-term Debt, Fiscal Year Maturity
2018 (remainder)	$ 7,412
2019	76,063
2020	123,705
2021	170,159
2022	141,724
Thereafter through 2039	784,062
Long term debt gross	1,303,125
Unamortized deferred financing costs	(7,117)
Unamortized premium, net	1,181
Debt, net	$ 1,297,189	$ 1,275,448

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after accumulated amortization, of debt discount (premium).

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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