FAIR VALUE (Activity for Assets and Liabilities Measured on Recurring Level 3 Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Reclassification of net fair value gains on sold/redeemed bonds	$ 21,875	$ 620
Net unrealized gains (losses) arising during the period	5,620	4,216
Derivative Liabilities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning period	(46)
Balance at ending period		(46)
Investments in Debt Securities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at start of period	143,604
Balance at end of period		143,604
Reclassification of net fair value gains on sold/redeemed bonds	21,900
Net unrealized gains (losses) arising during the period	5,600
Derivative Assets
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning period	2,347
Balance at ending period		2,347
Level 3 | Derivative Liabilities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning period	(46)	(372)
Net (losses) gains included in earnings	(41)	326
Impact from settlements	87
Balance at ending period		(46)
Level 3 | Investments in Debt Securities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at start of period	143,604	155,981
Net (losses) gain included in earnings	(6)	(5,265)
Net change in AOCI (1)	(16,249)	3,461
Impact from deconsolidation	17,998
Impacts from sales/redemptions	(47,488)	(6,784)
Impacts from settlements	(669)	(3,789)
Balance at end of period	(97,190)	143,604
Reclassification of net fair value gains on sold/redeemed bonds		600
Net unrealized gains (losses) arising during the period		4,200
Reclassification of realized losses (gains) to the Consolidated Statements of Operations related to bond investments assessed as other-than-temporary-impairment ("OTTI")		100
Level 3 | Loans Held for Investment
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at start of period		3,835
Net (losses) gain included in earnings		(5,335)
Impacts from purchases		14,028
Impact from originations		1,500
Impacts from sales/redemptions		(14,028)
Level 3 | Derivative Assets
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning period	2,347	2,327
Net (losses) gains included in earnings	854	20
Impact from settlements	(2,071)
Balance at ending period	$ 1,130	$ 2,347