Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities (Tables)

6 Months Ended

Jun. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Derivative Instruments [Table Text Block]

The following table summarizes the notional amounts and fair values of our designated cash flow hedges as of June 30, 2018 and December 31, 2017 (in thousands):

	Notional Amount				Fair Value at June 30, 2018 (USD)				Fair Value at December 31, 2017 (USD)
	June 30, 2018		December 31, 2017		Other Assets		Other Noncurrent Liabilities		Other Assets		Other Noncurrent Liabilities
Interest rate swap agreements
USD denominated	$	590,000	$	590,000	$	25,415	$	—	$	19,102	$	—
Cross currency swap agreements
USD/euro	$	398,614	$	406,546	10,382		52,208		5,504		61,492
Total cash flow hedges					$	35,797	$	52,208	$	24,606	$	61,492