Shareholders' Equity - Schedule of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	$ 8,289,545	$ 7,906,889	$ 7,213,156	$ 6,791,203	$ 7,906,889	$ 6,791,203
Other comprehensive income (loss) before reclassifications					74,288	195,777
Amounts reclassified from accumulated other comprehensive income					1,488	2,283
Net current-period other comprehensive income (loss)	121,723	(45,947)	137,939	60,121	75,776	198,060
Shareholders' equity, ending balance	8,983,231	8,289,545	7,820,925	7,213,156	8,983,231	7,820,925
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					(230)	(129)
Amounts reclassified from accumulated other comprehensive income					0	0
Net current-period other comprehensive income (loss)					(230)	(129)
Shareholders' equity, ending balance	(183)		109		(183)	109
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					74,518	195,906
Amounts reclassified from accumulated other comprehensive income					1,488	2,283
Net current-period other comprehensive income (loss)					76,006	198,189
Shareholders' equity, ending balance	145,762		140,362		145,762	140,362
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	23,856	69,803	2,532	(57,589)	69,803	(57,589)
Net current-period other comprehensive income (loss)	121,723	(45,947)	137,939	60,121
Shareholders' equity, ending balance	$ 145,579	$ 23,856	$ 140,471	$ 2,532	$ 145,579	$ 140,471