OFFESTTING OF ASSETS AND LIABILITIES - Offsetting of financial assets and liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Offsetting [Abstract]
Gross amount recognized of derivative asset	$ 368	$ 806
Gross amount of derivatives assets offset	0	0
Net asset amount of assets presented in the Statement of Financial Condition	368	806
Obligation to return Financial instrument, derivatives assets	(368)	(806)
Obligation to return Cash Collateral, derivative assets	0	0
Net derivative asset amount not offset	0	0
Gross amount recognized of derivative liabilities	0	0
Gross amount of derivative liabilities offset	0	0
Net derivative liability amount offset presented	0	0
Right to claim Financial instrument, derivatives liabilities	0	0
Right to claim Cash Collateral, derivatives liabilities	0	0
Net derivatives liability amount not offset	0	0
Gross amount recognized of repurchase agreements	600,000	600,000
Gross amount of repurchase agreements offset	(200,000)	(200,000)
Net repurchase agreements amount offset presented	400,000	400,000
Right to claim Financial instrument, repurchase agreements	(400,000)	(400,000)
Right to claim Cash Collateral, repurchase agreements	0	0
Net repurchase agreements amount not offset	0	0
Gross amount recognized of liabilities	600,000	600,000
Gross amount of liabilties offset	200,000	200,000
Net liabilities amount offset presented	400,000	400,000
Right to claim Financial instrument, liabilities	(400,000)	(400,000)
Right to claim Cash Collateral, liabilties	0	0
Net liability amount not offset	0	0
Securities Purchased Under Agreements To Resell Gross	200,000	200,000
Securities Purchased Under Agreements To Resell Liability	(200,000)	(200,000)
Securities Purchased Under Agreements To Resell Not Offset	0	0
Securities Purchased Under Agreements To Resell Collateral Obligation To Return Securities	0	0
Securities Purchased Under Agreements To Resell Collateral Obligation To Return Cash	0	0
Securities Purchased Under Agreements To Resell Amount Offset Against Collateral	0	0
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Gross	200,368	200,806
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Liability	(200,000)	(200,000)
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Liability Not Offset	368	806
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Collateral Obligation To Return Securities	(368)	(806)
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Collateral Obligation To Return Cash	0	0
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Amount Offset Against Collateral	$ 0	$ 0