OFFESTTING OF ASSETS AND LIABILITIES - Offsetting of financial assets and liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Offsetting [Abstract]
Gross amount recognized of derivative asset	$ 351	$ 11
Gross amount of derivatives assets offset	0	0
Net asset amount of assets presented in the Statement of Financial Condition	351	11
Obligation to return Financial instrument, derivatives assets	0	0
Obligation to return Cash Collateral, derivative assets	(351)	(11)
Net derivative asset amount not offset	0	0
Gross amount recognized of derivative liabilities	1,820
Gross amount of derivative liabilities offset	0
Net derivative liability amount offset presented	1,820
Right to claim Financial instrument, derivatives liabilities	(1,820)
Right to claim Cash Collateral, derivatives liabilities	0
Net derivatives liability amount not offset	0
Gross amount recognized of repurchase agreements	300,000	300,000
Gross amount of repurchase agreements offset	0	(200,000)
Net repurchase agreements amount offset presented	300,000	100,000
Right to claim Financial instrument, repurchase agreements	(300,000)	(100,000)
Right to claim Cash Collateral, repurchase agreements	0	0
Net repurchase agreements amount not offset	0	0
Gross amount of liabilties offset	0
Gross amount recognized of liabilities	301,820
Right to claim Cash Collateral, liabilties	0
Right to claim Financial instrument, liabilities	(301,820)
Net liabilities amount offset presented	301,820
Net liability amount not offset	0
Securities Purchased Under Agreements To Resell Gross	0	200,000
Securities Purchased Under Agreements To Resell Liability	0	(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
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Collateral Obligation To Return Securities	0	0
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Collateral Obligation To Return Cash	(351)	(11)
Securities Purchased Under Agreements To Resell Amount Offset Against Collateral	0	0
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Liability	0	(200,000)
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Amount Offset Against Collateral	0	0
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Gross	351	200,011
Derivative Asset Securities Purchased Under Agreements To Resell Securities Borrowed Liability Not Offset	$ 351	$ 11