DERIVATIVES - Derivative Financial Instruments, Average Remaining Maturity and the Weighted-Average Interest Rates being Paid and Received (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional Value	$ 894,227invest_DerivativeNotionalAmount	$ 823,585invest_DerivativeNotionalAmount
Interest Rate Swap
Derivative [Line Items]
Notional Value	894,227
Average Maturity (years)	4 years 2 months
Fair Value	(445)
Weighted-Average Rate Receive	3.61%
Weighted-Average Rate Pay	3.65%
Interest Rate Swap \| Pay fixed interest rate swaps with counterparty
Derivative [Line Items]
Notional Value	6,987
Average Maturity (years)	1 year 11 months
Fair Value	(377)
Weighted-Average Rate Receive	2.05%
Weighted-Average Rate Pay	6.85%
Interest Rate Swap \| Matched interest rate swaps \| Derivative Financial Instruments Receive Fixed Pay Variable
Derivative [Line Items]
Notional Value	443,620
Average Maturity (years)	4 years 2 months
Fair Value	14,352
Weighted-Average Rate Receive	4.59%
Weighted-Average Rate Pay	2.66%
Interest Rate Swap \| Matched interest rate swaps \| Derivative Financial Instruments Receive Variable Pay Fixed
Derivative [Line Items]
Notional Value	443,620
Average Maturity (years)	4 years 2 months
Fair Value	$ (14,420)
Weighted-Average Rate Receive	2.66%
Weighted-Average Rate Pay	4.59%

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

+ Details

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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Average variable interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

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- Details

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- Details

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