Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Summary of future minimum lease payments for operating leases
2012	$ 13,901
2013	12,382
2014	9,562
2015	7,872
2016	5,552
Thereafter	45,150
Total	94,419
Foreign [Member]
Summary of future minimum lease payments for operating leases
2012	1,836
2013	1,005
2014	789
2015	526
2016	268
Thereafter	167
Total	4,591
Domestic [Member]
Summary of future minimum lease payments for operating leases
2012	12,065
2013	11,377
2014	8,773
2015	7,346
2016	5,284
Thereafter	44,983
Total	$ 89,828