Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Assets:
Cash and cash equivalents	$ 36,584	$ 68,359
Short-term investments	13,170	26,829
Restricted cash	25,141	24,851
Other assets	6,817	6,442
Liabilities:
Deferred compensation	5,644	4,991
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	36,584	68,359
Short-term investments	13,170	26,829
Restricted cash	25,141	24,851
Other assets	0	0
Liabilities:
Deferred compensation	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Restricted cash	0	0
Other assets	6,817	6,442
Liabilities:
Deferred compensation	5,644	4,991
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Restricted cash	0	0
Other assets	0	0
Liabilities:
Deferred compensation	$ 0	$ 0