Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Tax Rate	31.00%	29.70%	26.20%
Income taxes paid	$ 74,700	$ 54,900	$ 60,200
Income tax ruling exemption	7,800	8,500	8,500
Cumulative earnings of non-United States subsidiaries considered to be indefinitely invested outside of United States	546,700
Unrecognized tax benefits	18,463	7,204	5,942	$ 6,325
Unrecognized tax benefits that would impact effective tax rate if recognized	5,900	5,900
Interest expense and penalties related to unrecognized tax benefits	300	300	$ 300
Interest expense and penalties accrued	600	$ 600
Net operating loss carryforwards in certain state and international jurisdictions	21,700
Valuation allowance against certain deferred tax assets related to net operating loss carryforwards	$ 4,900
Switzerland [Member]
Expiration date for tax holidays	December 31, 2015
Netherlands [Member]
Expiration date for tax holidays	December 31, 2022