SIGNIFICANT ACCOUNTING POLICIES - Benefits and Investment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SIGNIFICANT ACCOUNTING POLICIES
Premium paid for split dollar life insurance agreements	$ 0	$ 0	$ 0
Amount received on termination of certain split dollar agreements		$ 7,591	$ 6,496