Consolidated Statements of Cash Flow Cash, Cash Equivalents, and Restricted Cash - USD ($)	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 58,600,000	$ 56,000,000	$ 68,500,000
Short-term restricted cash included in other current assets	800,000	500,000.0	500,000
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	$ 59,400,000	$ 56,500,000	$ 69,000,000	$ 66,700,000