Other Income, Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Other Income (Expense), Net [Abstract]
Other income, net	$ 3,737	$ 4,766
Interest Income [Member]
Other Income (Expense), Net [Abstract]
Other income, net	5,622	4,773
Other Nonoperating Income [Member]
Other Income (Expense), Net [Abstract]
Other income, net	922	864
Insurance Policy Expense [Member]
Other Income (Expense), Net [Abstract]
Other income, net	(2,799)	(871)
Other Nonoperating Expense [Member]
Other Income (Expense), Net [Abstract]
Other income, net	$ (8)	$ 0