Derivative Financial Instruments (Fair Values of Derivative Instruments Designated as Cash Flow Hedges) (Details) - USD ($) $ in Thousands		Mar. 31, 2020		Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges, asset derivatives				$ 2,845
Derivatives designated as cash flow hedges, liability derivatives		$ (98,269)		(42,647)
Interest Rate Swap [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges, liability derivatives		(14,730)	[1]	(3,680)
Interest Rate Swap [Member] | Other Long-term Liabilities [Member}
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges, liability derivatives		$ (83,539)		(38,967)
Interest Rate Swap [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges, asset derivatives	[2]			$ 2,845

[1] Represents the estimated amount of the existing unrealized losses, respectively, on interest rate swaps as of March 31, 2020 (based on the interest rate yield curve at that date), included in AOCIL expected to be reclassified into pre-tax earnings within the next 12 months. The actual amounts reclassified into earnings are dependent on future movements in interest rates.

[2] In accordance with the derivatives and hedging guidance, the changes in fair values of interest rate swaps have been recorded in equity as a component of AOCIL. As the critical terms of the interest rate swaps match the underlying debt being hedged, all unrealized changes in fair value are recorded in AOCIL.