DERIVATIVES - Summary of Derivative Financial Instruments by Nature of Underlying Asset or Liability (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Notional Amount	$ 912,689	$ 935,493
Fair Value Hedges
Derivative [Line Items]
Notional Amount	$ 912,689	$ 935,493

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant