SECURED BORROWINGS - Schedule of Average Borrowings Outstanding (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Disclosure Of Repurchase Agreements [Abstract]
Average borrowings for the effects of related derivatives held as cash flow hedges	$ 12,503,039	$ 12,380,375
Effective borrowing rate considering cash flow hedges	1.08%	0.89%