Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Y	Dec. 31, 2011 Y	Dec. 31, 2009
Goodwill and Other Intangible Assets
Gross Carrying Amount	$ 99,132	$ 85,847
Weighted-Average Amortization Period (in years)	14	15
Accumulated Amortization	16,164	6,853
Net Carrying Amount	82,968	78,994
Intangibles not subject to amortization
Goodwill	126,267	120,045	6,507
Trademarks	15,455	15,455
Total goodwill and other intangible assets	224,690	214,494
Changes in goodwill
Goodwill, gross, balance at the beginning of the period	135,876	21,932
Additions through acquisitions, gross	6,222	113,944
Goodwill, gross, balance at the end of the period	142,098	135,876
Accumulated impairment, balance at the beginning of the period	(15,831)	(15,425)
Impairment loss		(406)
Accumulated impairment, balance at the end of the period	(15,831)	(15,831)
Goodwill, net, balance at the beginning of the period	120,045	6,507	6,507
Additions through acquisitions, Net	6,222	113,944
Goodwill, Impairment Loss		(406)
Goodwill, net, balance at the end of the period	$ 126,267	$ 120,045	$ 6,507