INVESTMENT AND MORTGAGE-BACKED SECURITIES, Fiscal Year Maturity and Other Disclosures (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) Security	Dec. 31, 2016 USD ($)	Sep. 01, 2008 USD ($) Security
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Reduction for previous credit losses realized on securities sold	$ 0	$ (1,229)	$ 0
OTTI and Non-credit Losses Recognized in Earnings and AOCI [Abstract]
Reductions for previous credit losses realized on securities sold during the year	0	(1,229)	0
Transfers [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Cumulative balance at the beginning of the period	0	756	807
Amortization		(50)	(51)
Reduction for previous credit losses realized on securities sold		(706)	0
Cumulative balance at end of the period		0	756
OTTI and Non-credit Losses Recognized in Earnings and AOCI [Abstract]
Reductions for previous credit losses realized on securities sold during the year		$ (706)	0
Pooled Bank Trust Preferred Securities ("TRUP CDOs") [Member]
Sale of TRUP CDO Securities [Abstract]
Number of TRUP CDO securities deemed OTTI | Security		5		8
Amortized cost of securities transferred		$ 5,331		$ 19,922
Unrealized loss on securities transferred recognized in accumulated other comprehensive income loss net of tax				$ 8,420
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Reduction for previous credit losses realized on securities sold		(9,077)
OTTI and Non-credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	0	9,157	9,295
(Amortization) Accretion of previously recognized OTTI		(80)	(138)
Reductions for previous credit losses realized on securities sold during the year		(9,077)
Cumulative pre-tax balance at end of the period		0	9,157
Pooled Bank Trust Preferred Securities ("TRUP CDOs") [Member] | Credit Related OTTI [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Reduction for previous credit losses realized on securities sold		(8,553)
OTTI and Non-credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	0	8,613	8,717
(Amortization) Accretion of previously recognized OTTI		(60)	(104)
Reductions for previous credit losses realized on securities sold during the year		(8,553)
Cumulative pre-tax balance at end of the period		0	8,613
Pooled Bank Trust Preferred Securities ("TRUP CDOs") [Member] | Non Credit Related OTTI [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Reduction for previous credit losses realized on securities sold		(524)
OTTI and Non-credit Losses Recognized in Earnings and AOCI [Abstract]
Cumulative pre-tax balance at the beginning of the period	0	544	578
(Amortization) Accretion of previously recognized OTTI		(20)	(34)
Reductions for previous credit losses realized on securities sold during the year		(524)
Cumulative pre-tax balance at end of the period		0	544
Registered Mutual Funds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Cumulative balance at the beginning of the period	0	0
Cumulative balance at end of the period	$ 0	$ 0	$ 0