XML 18 R24.htm IDEA: XBRL DOCUMENT v2.4.0.8
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Changes in Fair Value Level 2 Assets of Derivative Financial Instruments (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2013
Fair Value Disclosures [Line Items]    
Balance beginning of period $ 2,884 $ 11,651
Purchases and settlements (net) (2,881) (5,201)
Realized gains included in other income (expenses) 2,881 5,201
Unrealized gains (losses) included in other income (expenses) 640 (8,127)
Balance at end of period $ 3,524 $ 3,524