Goodwill and other intangible assets (Details) (USD $)	3 Months Ended		12 Months Ended
	Sep. 30, 2010	Jun. 30, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Acquired Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 200,000
Goodwill, Impairment Loss		21,400,000	0	21,438,000	111,700,000
Goodwill Subsequent Recognition of Deferred Tax Asset, Future Reductions			1,200,000
Goodwill			70,973,000	72,177,000
Intangible Assets, Net (Excluding Goodwill)		12,600,000	12,600,000	12,600,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)		34,600,000
Goodwill and Intangible Asset Impairment		56,000,000
Goodwill, Subsequent Recognition of Deferred Tax Asset			1,204,000	1,204,000	1,204,000
Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Amount			400,000
Finite-Lived Intangible Assets, Useful Life			5
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Amount			$ 1,200,000
Finite-Lived Intangible Assets, Useful Life			1