XML 82 R54.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Inventories (Details) (USD $)
Jun. 30, 2011
Dec. 31, 2010
Inventories    
Coal $ 189,989,000 $ 115,647,000
Repair parts and supplies, net of allowance 160,212,000 119,969,000
Inventories 350,201,000 235,616,000
Repair parts and supplies stated net of an allowance for slow-moving and obsolete inventories $ 13,100,000 $ 12,700,000