XML 32 R43.htm IDEA: XBRL DOCUMENT v2.4.0.6
Workers' Compensation Claims (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Summarizes aggregate workers' compensation reserve activity      
Workers' compensation claims liabilities, Beginning balance $ 51,193 $ 39,302 $ 35,958
Claims expense accrual:      
Current year 38,386 26,161 16,850
Prior years 12,352 9,978 880
Total expense accrual 50,738 36,139 17,730
Claim payments related to:      
Current year 6,746 5,565 3,814
Prior years 24,613 18,683 10,572
Total paid 31,359 24,248 14,386
Workers' compensation claims liabilities, Ending balance 70,564 51,193 39,302
Incurred but not reported (IBNR) $ 47,992 $ 37,335 $ 27,163