INVESTMENT AND MORTGAGE-BACKED SECURITIES, Reconciliation of Pre-Tax OTTI Charges Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
OTTI Credit and Non-Credit Losses Recognized in Earnings and AOCI [Abstract]
Reductions for previous credit losses realized on securities sold during the year			$ (1,229)	$ 0
Pooled Bank Trust Preferred Securities [Member]
OTTI Credit and Non-Credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	$ 9,088	$ 9,227	9,157	9,295
Amortization of previously recognized OTTI	(11)	(35)	(80)	(103)
Reductions for previous credit losses realized on securities sold during the year	(9,077)	0	(9,077)	0
Cumulative pre-tax balance at end of the period	0	9,192	0	9,192
Pooled Bank Trust Preferred Securities [Member] | Credit Related OTTI [Member]
OTTI Credit and Non-Credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	8,561	8,665	8,613	8,717
Amortization of previously recognized OTTI	(8)	(26)	(60)	(78)
Reductions for previous credit losses realized on securities sold during the year	(8,553)	0	(8,553)	0
Cumulative pre-tax balance at end of the period	0	8,639	0	8,639
Pooled Bank Trust Preferred Securities [Member] | Non-Credit Related OTTI [Member]
OTTI Credit and Non-Credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	527	562	544	578
Amortization of previously recognized OTTI	(3)	(9)	(20)	(25)
Reductions for previous credit losses realized on securities sold during the year	(524)	0	(524)	0
Cumulative pre-tax balance at end of the period	$ 0	$ 553	$ 0	$ 553