Fair Value Measurements and Derivatives Instruments - Summary of Effects on Consolidated Financial Statements of Designated As Cash Flow Hedges (Details) - Interest Rate Swaps - Cash Flow Hedges - Designated - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments Gain Loss [Line Items]
(Loss) income recognized in Other comprehensive income (loss)	$ (3,745)	$ 2,045	$ (9,820)	$ 9,127
Interest Expense
Derivative Instruments Gain Loss [Line Items]
Net loss reclassified from Accumulated other comprehensive loss into Interest expense	$ (2,199)	$ (2,513)	$ (5,634)	$ (7,344)