Financial Instruments (Details) - Interest Rate Swap [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ (14,018)	$ (4,676)
Contract One [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	125,000
Derivative, Net Liability Position, Aggregate Fair Value	(6,512)	(2,914)
Contract Two [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	75,000
Derivative, Net Liability Position, Aggregate Fair Value	(3,922)	(1,762)
Contract Three [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	75,000
Derivative, Net Liability Position, Aggregate Fair Value	(1,956)	0
Contract Four [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	50,000
Derivative, Net Liability Position, Aggregate Fair Value	(1,311)	0
Contract Five [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	25,000
Derivative, Net Liability Position, Aggregate Fair Value	$ (317)	$ 0