Schedule II - Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 15,222		$ 16,363		$ 15,474
Additions	928		763		2,596
Deductions	665	[1]	1,904	[1]	1,707	[1]
Balance at End of Period	$ 15,485		$ 15,222		$ 16,363

[1] Deductions represent amounts that the Company had fully reserved for in prior periods and pursuit of collection of such amounts was ceased during the period.