We lease office, retail and storage space to tenants, primarily under non-cancellable operating leases, which have terms generally ranging from five to fifteen years. Most of our leases provide tenants with extension options at either fixed or market rates and few of our leases provide tenants with options to early terminate, but such options generally impose an economic penalty on the tenant upon exercising. Our leases provide for (i) fixed payments of cash rents, which represents revenue each tenant pays in accordance with the terms of its respective lease and that is recognized on a straight-line basis over the non-cancellable term of the lease, and includes the effects of rent steps and rent abatements under the leases and (ii) variable payments of tenant reimbursements, which are recoveries of all or a portion of the operating expenses and real estate taxes of the property and is recognized in the same period as the expenses are incurred.

	For the Three Months Ended March 31,
(Amounts in thousands)	2020		2019
Rental revenues:
Fixed	$	160,676	$	160,318
Variable		14,749		15,023
Total rental revenues	$	175,425	$	175,341

The following table is a schedule of future undiscounted cash flows under non-cancelable operating leases in effect as of March 31, 2020, for the nine-month period from April 1, 2020 through December 31, 2020 and each of the five succeeding years commencing January 1, 2021.

(Amounts in thousands)
2020	$	464,057
2021		624,266
2022		602,003
2023		578,084
2024		550,189
2025		489,347
Thereafter		2,328,231
Total	$	5,636,177