Shareholders' Equity - Schedule of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	$ 8,983,231	$ 8,289,545	$ 7,906,889	$ 7,820,925	$ 7,213,156	$ 6,791,203	$ 7,906,889	$ 6,791,203
Other comprehensive income (loss) before reclassifications							233,175	115,403
Amounts reclassified from accumulated other comprehensive income							2,232	3,425
Net current-period other comprehensive income (loss)	159,631	121,723	(45,947)	(79,232)	137,939	60,121	235,407	118,828
Shareholders' equity, ending balance	9,268,171	8,983,231	8,289,545	7,773,758	7,820,925	7,213,156	9,268,171	7,773,758
Available- for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance			47			238	47	238
Other comprehensive income (loss) before reclassifications							(336)	(165)
Amounts reclassified from accumulated other comprehensive income							0	0
Net current-period other comprehensive income (loss)							(336)	(165)
Shareholders' equity, ending balance	(289)			73			(289)	73
Interest Rate Agreement Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance			69,756			(57,827)	69,756	(57,827)
Other comprehensive income (loss) before reclassifications							233,511	115,568
Amounts reclassified from accumulated other comprehensive income							2,232	3,425
Net current-period other comprehensive income (loss)							235,743	118,993
Shareholders' equity, ending balance	305,499			61,166			305,499	61,166
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	145,579	23,856	69,803	140,471	2,532	(57,589)	69,803	(57,589)
Net current-period other comprehensive income (loss)	159,631	121,723	(45,947)	(79,232)	137,939	60,121
Shareholders' equity, ending balance	$ 305,210	$ 145,579	$ 23,856	$ 61,239	$ 140,471	$ 2,532	$ 305,210	$ 61,239