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

Remainder of 2019	$	44,633
2020		86,163
2021		81,218
2022		80,346
2023		79,107
Thereafter		522,934
Total undiscounted lease payments		894,401
Imputed interest		(215,988	)
Total operating lease liabilities	$	678,413
Weighted average remaining lease term	11.8 years
Weighted average discount rate		4.59	%

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 $22.0 million and $22.1 million for the three months ended June 30, 2019 and 2018, respectively. Operating lease costs were $43.5 million and $44.1 million for the six months ended June 30, 2019 and 2018, respectively.

As of June 30, 2019, the Company had a total lease portfolio of 32 aircraft engines with a net book value of $306.5 million, which is included in fixed assets, net in the consolidated statements of financial condition.

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

Remainder of 2019	$	13,482
2020		24,598
2021		20,162
2022		11,980
2023		6,865
Thereafter		11,737
	$	88,824

Lease income, included in other income in the consolidated statements of operations, was $5.1 million and $13.3 million for the three and six months ended June 30, 2019, respectively.