Other Expense, Net (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Summary of other income, net
Interest income		$ 5,974	$ 2,017	$ 10,947	$ 4,002
Interest expense	[1]	(12,916)	(12,694)	(25,757)	(25,291)
Net loss on foreign exchange and foreign currency derivative contracts		(3,854)	(1,944)	(5,912)	(6,380)
Fair value adjustment on other derivative		(2,200)	0	(4,500)		$ 0
Other non-operating income, net		429	155	516	461
Net realized gain on sales of marketable securities		24	66	105	161
Other expense, net		(12,543)	(12,400)	$ (24,601)	(27,047)
Interest costs capitalized		$ 600	$ 300		$ 500

[1] The Company capitalized $0.6 million and $0.3 million of interest expense related to properties under construction for the three months ended June 30, 2016 and 2015, respectively, and $1.1 million and $0.5 million for the six months ended June 30, 2016 and 2015, respectively.