DERIVATIVES - Summary of Derivative Financial Instruments by Nature of Underlying Asset or Liability (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Notional Amount	$ 819,038	$ 775,328
Fair Value Hedges
Derivative [Line Items]
Notional Amount	$ 819,038	$ 775,328

Aggregate notional amount of all derivatives. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Name:	us-gaap_NotionalAmountOfDerivatives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant