OTHER COMPREHENSIVE INCOME (LOSS) (Details) - Total Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net income	$ (11,950)	$ 9,553	$ 5,045	$ 12,264	$ 5,531	$ 7,596	$ 6,095	$ 10,788	$ 14,912	$ 30,010	$ 34,289
Other comprehensive income (loss), net of taxes									20,760	9,947	(61,124)
Comprehensive income (loss), net									$ 35,672	$ 39,957	$ (26,835)