Convertible and Long-term Debt Obligations - MyPower Revolving Credit Facility - Additional Information (Detail) - SolarCity [Member] - Non-recourse debt [Member] - MyPower Revolving Credit Facility [Member] - Revolving Credit Facility [Member] - USD ($) $ in Millions				12 Months Ended
	Jan. 27, 2017	Dec. 16, 2015	Jan. 09, 2015	Dec. 31, 2017
Debt Instrument [Line Items]
Credit facility interest rate terms				The Class A notes bore interest at an annual rate of 2.50% plus (a) the commercial paper rate or (b) 1.50% plus adjusted LIBOR. The Class B notes bore interest at an annual rate of 5.00% plus LIBOR.
Outstanding principal amount repaid	$ 133.8
Class A [Member]
Debt Instrument [Line Items]
Credit facility interest rate terms				The fee for undrawn commitments under the Class A notes was 0.50% per annum.
Interest Rate			2.50%
Percentage of fee for undrawn commitments			0.50%
LIBOR [Member]
Debt Instrument [Line Items]
Line of credit, additional interest rate			1.50%
Class B [Member]
Debt Instrument [Line Items]
Credit facility interest rate terms				The fee for undrawn commitments under the Class B notes was 0.50% per annum.
Line of credit, additional interest rate		5.00%
Percentage of fee for undrawn commitments			0.50%