Summary of Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 1,154,784	$ 1,095,973	$ 873,600
Under Customer Agreements:
Deferred Revenue Arrangement [Line Items]
Deferred revenue	935,098	906,097
Under Customer Agreements: | Payments received, net
Deferred Revenue Arrangement [Line Items]
Deferred revenue	864,546	840,771
Under Customer Agreements: | Financing component balance
Deferred Revenue Arrangement [Line Items]
Deferred revenue	70,552	65,326
Under SREC contracts:
Deferred Revenue Arrangement [Line Items]
Deferred revenue	219,686	189,876
Under SREC contracts: | Payments received, net
Deferred Revenue Arrangement [Line Items]
Deferred revenue	207,908	179,416
Under SREC contracts: | Financing component balance
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 11,778	$ 10,460