FAIR VALUE DISCLOSURES - Summary of Financial Assets and Liabilities Measure at Fair Value on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets
Derivatives	$ 12,445	$ 13,477
Available-for-sale investment securities	862,526	913,601
Liabilities
Derivatives	13,427	14,431
Fair Value, Measurements, Recurring
Assets
Derivatives	0	0
Available-for-sale investment securities	862,526	913,601
Total	862,526	913,601
Liabilities
Derivatives	982	954
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 1
Assets
Derivatives	0	0
Available-for-sale investment securities	8,050	7,976
Total	8,050	7,976
Liabilities
Derivatives	0	0
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 2
Assets
Derivatives	12,445	13,477
Available-for-sale investment securities	854,476	905,625
Total	866,921	919,102
Liabilities
Derivatives	13,427	14,431
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 3
Assets
Derivatives	0	0
Available-for-sale investment securities	0	0
Total	0	0
Liabilities
Derivatives	0	0
Fair Value, Measurements, Recurring | Netting Adjustments
Assets
Derivatives	(12,445)	(13,477)
Available-for-sale investment securities	0	0
Total	(12,445)	(13,477)
Liabilities
Derivatives	$ (12,445)	$ (13,477)