Commitments and Contingencies (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Commitments and Contingencies (Textual) [Abstract]
Potential liability audit ranges Minimum	$ 2,900,000
Potential liability audit ranges Maximum	13,600,000
Accrual estimated liability	2,900,000
Relocation severance and retention plans expenses	1,000,000
Additional relocation expenses	6,200,000
Self insurance deductible for workers compensation	750,000
Self insurance deductible for general liability claims	750,000
Self insurance deductible for medical and dental coverage	300,000
Self insured risk accruals	21,100,000	19,700,000
Recievable for Medical and Dental Coverage	$ 452,000	$ 1,000