Financial Instruments Financial Instruments - Level 3 Changes in Fair Value (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Fair Value, Measurements, Recurring [Member]
Derivative [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$ 32
Derivative Assets (Liabilities), at Fair Value, Net	5,242
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,100)
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Derivative [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	1,228
Derivative Assets (Liabilities), at Fair Value, Net	(130)
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	1,228
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0
Derivative, Gain (Loss) on Derivative, Net	(1,074)	[1]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	(284)
Derivative Assets (Liabilities), at Fair Value, Net	$ (130)

[1] *Gains and losses related to interest rate swaps are recorded in interest expense in the condensed consolidated statements of operations and comprehensive income (loss).