Derivative Financial Instruments Effectiveness Testing (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Rate Swap [Member]
Gain/(loss) reclassified from accumulated other comprehensive income/(loss) into earnings due to ineffectiveness	$ 0	$ 0	$ 0
Existing net losses realized and recorded as interest expense	(2,100,000)	(2,100,000)	(2,900,000)
Existing net losses expected to be realized within the next 12 months	(2,000,000)
Foreign Exchange Forward [Member]
Gain/(loss) reclassified from accumulated other comprehensive income/(loss) into earnings due to ineffectiveness	0	$ 0	$ 0
Existing net losses expected to be realized within the next 12 months	$ 600,000