SECURITIES (Textuals) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($) security	Dec. 31, 2014 USD ($) security
Trading:
Trading securites, proceeds from sale	$ 7,839,000	$ 4,419,000	$ 2,387,000
Trading Securities, Realized Gain (Loss)	530,000	(690,000)	1,000
Trading securities, OTTI charges	$ 0	$ 0	$ 0
Trading securities, number of securities in nonaccrual status | security	0	0	0
Trading securities, unrealized holding gain	$ (376,000)	$ 2,000,000
Available-for-Sale:
Available-for-sale securities, unrealized loss position, number of securities | security	243	242	94
Available-for-sale securities, proceeds from sale	$ 369,800,000	$ 232,600,000	$ 56,300,000
Available-for-sale securities, Realized Gain (Loss)	311,000	126,000	41,000
Available-for-sale securities, OTTI charges	$ 0	$ 0	$ 0
Available-for-sale Securities, Number of Securities in Nonaccrual Status | security	0	0	0
Held-to-Maturity:
Held-to-maturity Securities, unrealized loss position, number of securities | security	73	32	25
Held-to-maturity Securities, proceeds from sale	$ 0	$ 0	$ 0
Held-to-maturity securities, number of securities in nonaccrual status | security	0	0	0