SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Restricted cash (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
RESTRICTED CASH AND CASH EQUIVALENTS
Restricted cash and cash equivalents	$ 39,100	$ 29,600
Restricted cash and cash equivalents from initial capitalization of captive company	2,000
Additional cash and cash equivalents restricted at the election of management for potential insurance claims	27,700
MOTIVE Merger
RESTRICTED CASH AND CASH EQUIVALENTS
Restricted cash and cash equivalents	9,400
Prepaid expenses and other
RESTRICTED CASH AND CASH EQUIVALENTS
Restricted cash and cash equivalents	32,439	27,631
Other assets.
RESTRICTED CASH AND CASH EQUIVALENTS
Restricted cash and cash equivalents	$ 6,695	$ 2,000