SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE - Repurchase Agreements Grouped by Counterparty (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Repurchase Agreement Counterparty [Line Items]
Maximum aggregate balance outstanding	[1],[2]	$ 300,000	$ 700,000
Jp Morgan Chase [Member]
Repurchase Agreement Counterparty [Line Items]
Maximum aggregate balance outstanding		$ 200,000
Weighted-Average Maturity		5 years 1 month
Dean Witter Morgan Stanley [Member]
Repurchase Agreement Counterparty [Line Items]
Maximum aggregate balance outstanding		$ 100,000
Weighted-Average Maturity		10 months

[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.