Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary of Significant Accounting Policies

Schedule of workers' compensation liabilities

	December 31,
	2011		2010
Undiscounted aggregated estimated claims to be paid	$	43,501	$	45,497
Workers' compensation liability recorded on a discounted basis	$	36,987	$	37,761