Retirement Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Domestic Pension Plan [Member]
Components of net periodic benefit cost
Interest cost	$ 821	$ 865	$ 1,642	$ 1,730
Expected return on plan assets	(918)	(914)	(1,836)	(1,828)
Recognized actuarial loss	216	115	432	230
Amortization of prior service credit	15	109	30	218
Net periodic benefit cost	134	175	268	350
International Pension Plan [Member]
Components of net periodic benefit cost
Interest cost	200	237	400	474
Service cost	165	160	330	320
Recognized actuarial loss	50	28	100	56
Amortization of prior service credit	(2)	(2)	(4)	(4)
Net periodic benefit cost	413	423	826	846
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Components of net periodic benefit cost
Net periodic benefit cost	$ 55	$ 66	$ 110	$ 132