Acquisitions and Dispositions (Details 4) (Series of Individually Immaterial Business Acquisitions [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010
Acquired Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 9,205	$ 3,830
Covenants not to compete [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets	203	150
Useful life	5 years
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets	0	430
Useful life	10 years
Licensing Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Not amortizable intangible assets	$ 9,002	$ 3,250