Acquisitions and Dispositions (Details 3) (Series of Individually Immaterial Business Acquisitions [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2010
Series of Individually Immaterial Business Acquisitions [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fixed assets, net	$ 509	$ 269
Identifiable intangible assets	9,205	3,830
Goodwill	14,695	4,546
Other assets	66	12
Total assets aquired	24,475	8,657
Accounts payable and accrued liabilities	(1,955)	0
Other liabilities	0	(157)
Total liabilities assumed	(1,955)	(157)
Net assets acquired	$ 22,520	$ 8,500