The table below presents information about operating lease liabilities as of September 30, 2019, (in thousands, except percentages).

Remainder of 2019	$	22,331
2020		86,712
2021		81,631
2022		80,779
2023		79,830
Thereafter		537,119
Total undiscounted lease payments		888,402
Imputed interest		(215,274	)
Total operating lease liabilities	$	673,128
Weighted average remaining lease term	11.4 years
Weighted average discount rate		4.60	%

In the table above, the weighted average discount rate represents our company’s incremental borrowing rate as of January 2019 for leases existing on the date of adoption of the new lease standard and at the lease inception date for leases entered into subsequent to the adoption of ASU 2016-02.

Operating lease costs, included in occupancy and equipment rental in the consolidated statements of operations, were $22.1 million and $21.5 million for the three months ended September 30, 2019 and 2018, respectively. Operating lease costs were $65.6 million and $65.6 million for the nine months ended September 30, 2019 and 2018, respectively.

As of September 30, 2019, the Company had a total lease portfolio of 13 aircraft engines with a net book value of $179.1 million, which is included in fixed assets, net in the consolidated statements of financial condition.

As of September 30, 2019, minimum future payments under non-cancelable leases were (in thousands):

Remainder of 2019	$	6,531
2020		24,598
2021		20,162
2022		11,980
2023		6,865
Thereafter		11,737
	$	81,873

Lease income, included in other income in the consolidated statements of operations, was $5.2 million and $18.5 million for the three and nine months ended September 30, 2019, respectively.