Debt Debt (Schedule of Maturities of Long-term Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Maturities of Long-term Debt [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	$ 1,155
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	1,196
2020	1,244
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	121,291
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	638,340
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	409,903
Long-term Debt, Gross	1,173,129
Debt Instrument, Unamortized Discount	(3,340)
Less: unamortized loan costs	(9,563)
Unamortized Debt Issuance Expense		$ 10,453
Debt, Long-term and Short-term, Combined Amount	$ 1,160,226	$ 1,145,497