Segment and Related Information (Reconciliation of Operating Profit or Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	$ 97,740	$ 98,849	$ (23,140)
Total Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	106,000	102,700	(14,600)
Unallocated Corporate Expenses [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	(5,700)	(4,500)	(2,500)
Interest Income [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	3,900	2,700	2,900
Interest Expense [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	(3,300)	(3,300)	(3,500)
Other Income (Deductions) [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from continuing operations before provision (benefit) for taxes	$ (3,200)	$ 1,200	$ (5,400)