HA Sustainable Infrastructure Capital, Inc. Quarterly report pursuant to Section 13 or 15(d)

Equity - Schedule of Common Stock Public Offerings and ATM (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Proceeds				$ 15,326	$ 98,316
1/20/17 to 2/2/17 Closing Date [Member] \| ATM [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued (in shares)			197
Price Per Share (in usd per share)			$ 19.18
Net Proceeds			$ 4,000
3/10/2017 Closing Date [Member] \| Public Offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued (in shares)			3,450
Price Per Share (in usd per share)			$ 18.73
Net Proceeds			$ 64,000
5/17/17 to 6/22/17 Closing Date [Member] \| ATM [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued (in shares)		1,376
Price Per Share (in usd per share)		$ 22.71
Net Proceeds		$ 31,000
5/18/2018 to 6/25/2018 Closing Date [Member] \| ATM [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued (in shares)	834
Price Per Share (in usd per share)	$ 18.76
Net Proceeds	$ 15,000