Retirement Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Domestic Plan
Components of net periodic pension cost
Service cost	$ 12,000	$ 4,000
Interest cost	770,000	850,000
Expected return on plan assets	(1,138,000)	(1,046,000)
Amortization of net loss	365,000	313,000
Net periodic pension cost	9,000	121,000
Employer contributions	200,000
Domestic Plan | Annual estimate
Components of net periodic pension cost
Anticipated contributions	2,300,000
Foreign Plans
Components of net periodic pension cost
Service cost	142,000	113,000
Interest cost	374,000	405,000
Expected return on plan assets	(144,000)	(118,000)
Amortization of prior service credit	(13,000)	(13,000)
Amortization of net loss	136,000	12,000
Net periodic pension cost	495,000	399,000
Pension plan of U.K. subsidiary
Components of net periodic pension cost
Employer contributions	200,000
Pension plan of U.K. subsidiary | Annual estimate
Components of net periodic pension cost
Anticipated contributions	700,000
Pension plan of German subsidiaries
Components of net periodic pension cost
Payments made	300,000
Pension plan of German subsidiaries | Annual estimate
Components of net periodic pension cost
Expected 2013 benefit payments	$ 1,300,000