REVENUE - TIMING OF REVENUE RECOGNITION - BALANCE SHEET (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Customer accounts receivable
Billed	$ 273,924	$ 205,490
Unbilled revenues	42,850	7,199
Customers' credit	(18,162)	$ (27,325)
Customers accounts receivables & Customers' credit balances and deposits	298,612
Operating Segments | Natural Gas Distribution
Customer accounts receivable
Billed	113,472
Unbilled revenues	42,850
Customers' credit	(18,159)
Customers accounts receivables & Customers' credit balances and deposits	138,163
Operating Segments | Clean Energy Ventures
Customer accounts receivable
Billed	2,557
Unbilled revenues	0
Customers' credit	0
Customers accounts receivables & Customers' credit balances and deposits	2,557
Operating Segments | Energy Services
Customer accounts receivable
Billed	156,349
Unbilled revenues	0
Customers' credit	0
Customers accounts receivables & Customers' credit balances and deposits	156,349
Home Services and Other
Customer accounts receivable
Billed	2,344
Unbilled revenues	0
Customers' credit	(3)
Customers accounts receivables & Customers' credit balances and deposits	2,341
Eliminations
Customer accounts receivable
Billed	798
Unbilled revenues	0
Customers' credit	0
Customers accounts receivables & Customers' credit balances and deposits	$ 798