We have various non-cancelable lease agreements for certain of our offices with original lease periods expiring between 2021 and 2042. Our lease terms may include options to extend or terminate the lease when it is reasonably certain we will exercise that option. Certain of the arrangements have free rent periods or escalating rent payment provisions. Leases with an initial term of twelve months or less are not recorded on the consolidated balance sheets. We recognize rent expense on a straight-line basis over the lease term. Additionally, we sublease certain operating leases to third parties primarily as a result of moving to a centralized corporate office in Santa Monica, California in 2018.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
	(in thousands)
Operating lease expense	$	17,795		$	15,335		$	49,883		$	45,074
Sublease income		(682	)		(755	)		(2,010	)		(2,290	)
Total net lease costs	$	17,113		$	14,580		$	47,873		$	42,784

The weighted-average remaining lease term (in years) and discount rate related to the operating leases were as follows:

	Nine Months Ended September 30,
	2021			2020
Weighted-average remaining lease term		6.9			7.5
Weighted-average discount rate		5.2	%		5.6	%

As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the lease commencement date to determine the present value of lease payments.

The present value of our operating lease liabilities as of September 30, 2021 were as follows:

	Operating Leases
	(in thousands)
Remainder of 2021	$	13,571
2022		76,751
2023		71,471
2024		70,224
2025		64,877
Thereafter		119,417
Total lease payments	$	416,311
Less: Imputed interest		(67,614	)
Present value of lease liabilities	$	348,697

As of September 30, 2021, we have additional operating leases for facilities that have not yet commenced with lease obligations of $43.6 million. These operating leases will commence between 2021 and 2022 with lease terms of greater than one year to five years. This table does not include lease payments that were not fixed at commencement or modification.

Cash payments included in the measurement of our operating lease liabilities were $19.1 million and $18.3 million for the three months ended September 30, 2021 and 2020, respectively, and $54.1 million and $56.6 million for the nine months ended September 30, 2021 and 2020, respectively.

Lease liabilities arising from obtaining operating lease right-of-use assets were $8.4 million and $56.1 million for the three and nine months ended September 30, 2021, respectively. Lease liabilities arising from obtaining operating lease right-of-use assets were $24.0 million for the nine months ended September 30, 2020 and were not material for the three months ended September 30, 2020.