Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets held under capital leases and included in property, plant and equipment
Gross amounts capitalized	$ 12,006	$ 16,117
Accumulated amortization	(7,485)	(10,510)
Net assets under capital leases	4,521	5,607
Buildings [Member]
Assets held under capital leases and included in property, plant and equipment
Gross amounts capitalized	3,100	3,100
Accumulated amortization	(1,899)	(1,821)
Equipment [Member]
Assets held under capital leases and included in property, plant and equipment
Gross amounts capitalized	8,906	13,017
Accumulated amortization	$ (5,586)	$ (8,689)