Balance Sheet Related Information (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Balance Sheet Related Information (Textual) [Abstract]
Pension adjustments, net of tax	$ 113	$ 134
Tax benefit on actuarial loss on pension plans	6,944	1,938
Tax benefit on unrealized loss on interest rate swap agreement	3,329	2,440
Tax benefit (expense) on unrealized gain on available-for-sale securities	$ 0	$ 1,022