Current Assets and Current Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Receivables
Balance at beginning of year	$ 3,538	$ 2,777	$ 2,423
Charged to expense	1,424	2,022	1,302
Accounts written off	(1,152)	(1,261)	(948)
Balance at end of year	3,810	3,538	2,777
Other Receivables
Allowance for other receivables			$ 9,000
Reserve on note receivable and other contractual payments due from a specific buyer of some of the coal cleaning facilities (as a percent)			100.00%
Gain on disposal of discontinued operations resulting from collection of receivable		2,000
Inventories
Raw materials	12,831	12,017
Finished goods	42,243	38,616
Inventories	55,074	50,633
Warranty Liabilities
Balance at beginning of year	7,219	2,141	$ 1,834
Charged to expense	2,020	1,992	1,629
Changes to prior year estimates	(461)	32	0
Additions from acquisitions	0	4,842	40
Payments for claims	(2,010)	(1,788)	(1,362)
Balance at end of year	6,768	7,219	$ 2,141
Other Accrued Liabilities
Products and services received but not yet invoiced	24,215	19,870
Other	25,271	21,887
Other Accrued Liabilities, Current	$ 49,486	$ 41,757