Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effective Tax Rate	26.20%	28.70%	31.60%
Income tax ruling exemption	$ 8,500,000	$ 6,500,000	$ 6,000,000
Cumulative earnings of non-United States subsidiaries considered to be indefinitely invested outside of United States	431,700,000
Unrecognized tax benefits	5,942,000	6,325,000	5,906,000	5,149,000
Unrecognized tax benefits that would impact effective tax rate if recognized	5,000,000	5,700,000
Interest expense and penalties related to unrecognized tax benefits	300,000	300,000	300,000
Interest expense and penalties accrued	500,000	600,000
Positions for which it is reasonably possible that total amount of unrecognized tax benefits will significantly increase or decrease within 12 months of reporting date	400,000
Net operating loss carryforwards in certain state and international jurisdictions	41,600,000
Valuation allowance against certain deferred tax assets related to net operating loss carryforwards	$ 4,700,000
Tax years no longer subject to U.S. federal examination [Member]
Years before	2013
With few exceptions, tax years no longer subject to state or local and international jurisdicition examination [Member]
Years before	2006
Switzerland [Member]
Expiration date for tax holidays	December 31, 2015
Netherlands [Member]
Expiration date for tax holidays	December 31, 2022