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
	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments Gain Loss [Line Items]
(Loss) income recognized in Other comprehensive income	$ (4,157)	$ 2,867
Interest Expense
Derivative Instruments Gain Loss [Line Items]
Net loss reclassified from Accumulated other comprehensive loss into Interest expense	$ (836)	$ (2,607)