Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Valuation allowance on deferred tax assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	$ 4,217		$ 5,221		$ 5,000
Charged to Cost and Expense	(250)		(998)		236
Others	(181)		(6)		(15)
Balance End of Period	3,786		4,217		5,221
Allowance for doubtful accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	3,831		2,407		2,172
Charged to Cost and Expense	1,337		2,127		1,547
Others (A)	49	[1]	502	[1]	0	[1]
Deductions (B)	1,923	[2]	1,205	[2]	1,312	[2]
Balance End of Period	$ 3,294		$ 3,831		$ 2,407

[1] (A)Additions to allowance for doubtful accounts attributable to acquisitions.

[2] (B)Write-off of bad debts, net of recoveries.