Goodwill and Other Intangible Assets (Narrative) (Details) (USD $)	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Amortization of Intangible Assets
Amortization of intangible assets	$ 2,837,000	$ 3,313,000	$ 3,717,000	$ 7,610,000	$ 5,090,000	$ 4,407,000	$ 3,839,000	$ 9,867,000	$ 13,336,000	$ 20,946,000	$ 22,201,000
Estimated amortization of intangible assets, remainder of 2013	4,000,000							4,000,000
Estimated amortization of intangible assets, 2014	11,000,000							11,000,000
Estimated amortization of intangible assets, 2015	9,000,000							9,000,000
Estimated amortization of intangible assets, 2016	8,000,000							8,000,000
Estimated amortization of intangible assets, 2017	5,000,000							5,000,000
Estimated amortization of intangible assets, 2018	4,000,000							4,000,000
Estimated amortization of intangible assets, after 2018	$ 3,000,000							$ 3,000,000