Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Changes in goodwill
Goodwill, net, balance at the beginning of the period	$ 120,045
Additions through acquisitions, gross	3,811
Goodwill, net, balance at the end of the period	123,856
Other intangible assets, net:
Other intangible assets, net, balance at beginning of the period	94,449
Purchases of intangible assets	11,763
Amortization expense	(6,479)
Other intangible assets, net, balance at end of the period	99,733
Accumulated Amortization	$ 13,332	$ 6,853