SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE - Schedule of Repurchase Agreement Maturity (Detail) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Repurchase Agreement [Line Items]
Securities Sold Under Agreements To Repurchase	[1],[2]	$ 300,000	$ 700,000
Securities Sold Under Agreements To Repurchase Mature Over Five Years [Member]
Repurchase Agreement [Line Items]
Securities Sold Under Agreements To Repurchase		200,000
Securities Sold Under Agreements To Repurchase Mature Six Months To One Year [Member]
Repurchase Agreement [Line Items]
Securities Sold Under Agreements To Repurchase		$ 100,000

[1] As of December 31, 2016, includes $200 million that have an average rate of 2.11% and that are callable by lenders before their contractual maturities at various dates beginning on January 19, 2017. Subsequent to December 31, 2016, no lender has exercised its call option on repurchase agreements. In addition, $100 million is tied to variable rates.

[2] Reported net of securities purchased under agreements to repurchase (reverse repurchase agreements) by counterparty, when applicable, pursuant to ASC 210-20-45-11.