SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Securities sold under agreements to repurchase
Securities sold under agreements to repurchase	$ 26,158	$ 11,800	$ 36,263
Carrying amount of U.S. GSE, mortgage-backed securities and collateralized mortgage obligations that serve as securities under repurchase agreements	29,300	14,400	403,000
Fourth quarter of 2015
Securities sold under agreements to repurchase
Securities sold under agreements to repurchase	26,200
Securities sold under agreement to repurchase
Securities sold under agreements to repurchase
Average daily balance	$ 28,233	$ 11,581	$ 14,185
Average interest rate (as a percent)	0.64%	3.21%	2.71%
Maximum month-end balance	$ 36,230	$ 12,045	$ 36,879
Weighted average interest rate (as a percent)	0.64%	3.18%	2.67%