Fair Value of Financial Instruments - Schedule of Estimated Fair Values and Carrying Values (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	$ 8,828,985	$ 5,892,016
Senior Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	1,775,550
Fair Value	1,732,500
Convertible senior notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	3,722,673	2,957,288
Fair Value	4,488,651	3,205,641
Participation interest [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	17,545	16,713
Fair Value	17,042	15,025
Solar asset-backed notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	880,415	442,764
Fair Value	898,145	428,551
Solar Loan-backed Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying Value	236,844	137,024
Fair Value	$ 248,149	$ 132,129