	December 31, 2018		March 31, 2019
	(In millions)
Other noncurrent assets:
Land held for development	$	129.2	$	126.2
Operating lease right-of-use assets		—		33.1
Restricted cash and cash equivalents		8.9		8.6
Land contract receivables		9.1		3.8
IBNR receivables		6.0		6.9
Marketable securities		4.8		4.9
Pension asset		2.7		3.4
Notes receivable - OPA		1.9		3.1
Other		12.7		13.7
Total	$	175.3	$	203.7

Land contract receivables classified as a noncurrent asset relate to our Real Estate Management and Development Segment. Such receivables relate to certain fees we collect from builders when the builder sells a home to a customer.

We enter into various arrangements (or leases) that convey the rights to use and control identified underlying assets for a period of time in exchange for consideration. We lease various manufacturing facilities and equipment. In addition, our Chemicals Segment’s principal German operating subsidiary leases the land under its Leverkusen TiO₂ production facility pursuant to a lease with Bayer AG that expires in 2050. The Leverkusen facility itself, which Kronos owns and which represents approximately one-third of our current TiO₂ production capacity, is located within Bayer’s extensive manufacturing complex. From time to time, we may also enter into an arrangement in which the right to use and control an identified underlying asset is embedded in another type of contract.

On January 1, 2019 we adopted Accounting Standards Update (“ASU 2016-02”), Leases (Topic 842). See Note 18. We determine if an arrangement is a lease (including leases embedded in another type of contract) at inception. All of our leases are classified as operating leases under this new ASU. Operating leases are included in operating lease right-of-use assets, current operating lease liabilities and noncurrent operating lease liabilities in our Condensed Consolidated Balance Sheet beginning January 1, 2019. See Notes 8 and 9.

Right-of-use assets represent our right to use an underlying asset for the lease term and operating lease liabilities represent our obligation to make lease payments arising from the lease. For leases in effect as of the January 1, 2019 date of adoption of the new ASU, the right-of-use operating lease assets and liabilities were recognized based on the estimated present value of remaining lease payments over the remaining lease term as of the adoption date. For new leases entered into subsequent to the date of adoption of the new ASU, the right-of-use operating lease asset and liabilities will be recognized based on the estimated present value of lease payments over the lease term as of the respective lease commencement dates.

We use an estimated incremental borrowing rate to determine the present value of lease payments (unless we can determine the rate implicit in the lease, which is generally not the case). Our incremental borrowing rate for each of our leases is derived from available information, including our current debt and credit facilities and U.S. and European yield curves as well as publicly available data for instruments with similar characteristics, adjusted for factors such as collateralization and term. For leases in effect as of the January 1, 2019 date of adoption of the new ASU, we used an estimated incremental borrowing rate for each lease on the date of adoption. For new leases entered into subsequent to the date of adoption of the new ASU, we use an estimated incremental borrowing rate for each lease as of the respective lease commencement dates.

Our leases generally do not include termination or purchase options. Certain of our leases include an option to renew the lease after expiration of the initial lease term, but we have not included such renewal periods in our lease term because it is not reasonably certain that we would exercise the renewal option. Our leases generally have fixed lease payments, with no contingent or incentive payments. Certain of our leases include variable lease payments that depend on a specified index or rate, and in accordance with ASU 2016-02 the determination of the operating lease liabilities is based on the index or rate existing at the date of adoption of the new ASU (for leases in effect as of January 1, 2019) or the index or rate in effect as of the lease commencement date (for leases entered into subsequent to the date of adoption of the new ASU). Our lease agreements do not contain any residual value guarantees.

With respect to our land lease associated with Kronos’ Leverkusen facility, we periodically establish the amount of rent for such land lease by agreement with Bayer for periods of at least two years at a time. The lease agreement provides for no formula, index or other mechanism to determine changes in the rent of such land lease; rather, any change in the rent is subject solely to periodic negotiation between Bayer and us. As such, we will account for any change in the rent associated with such lease subsequent to the January 1, 2019 adoption of the new ASU as a lease modification.

During the first three months of 2019, our operating lease expense approximated $2.1 million (which amount approximates the amount of cash paid during the period for our operating leases included in the determination of our net cash flows from operating activities). During the first three months of 2019, variable lease expense and short-term lease expense were not material. During the first three months of 2019, we entered into new operating leases which resulted in the recognition of a nominal right-of-use operating lease asset and operating lease liability. At March 31, 2019, the weighted average remaining lease term of our operating leases was approximately 13 years, and the weighted average discount rate associated with such leases was approximately 4.5%. Such average remaining lease term is weighted based on each arrangement’s lease obligation, and such average discount rate is weighted based on each arrangment’s total remaining lease payments.

Years ending December 31,	Amount
	(In millions)
Gross amounts due each year:
2019 (remainder of year)	$	5.8
2020		6.7
2021		6.0
2022		3.4
2023		2.2
2024 and thereafter		21.3
Total lease payments		45.4
Less imputed interest		13.0
Total lease obligations		32.4
Less current obligations		6.8
Long-term lease obligations	$	25.6

Net operating lease rent expense approximated $14.3 million in 2016, $16.3 million in 2017 and $14.8 million in 2018. At December 31, 2018, future minimum payments under non-cancellable operating leases having an initial or remaining term of more than one year were as follows:

Years ending December 31,	Amount
	(In millions)
2019	$	6.3
2020		5.1
2021		4.3
2022		3.2
2023		2.4
2024 and thereafter		21.5
Total (1)	$	42.8

(1)

Approximately $17 million of the $42.8 million aggregate future minimum rental commitments at December 31, 2018 relates to Kronos’ Leverkusen facility lease discussed above. The minimum commitment amounts for such lease included in the table above for each year through the 2050 expiration of the lease are based upon the current annual rental rate as of December 31, 2018. As discussed above, any change in the rent is based solely on negotiations between Bayer and Kronos, and any such change in the rent was deemed “contingent rentals” under prior GAAP and was excluded from the future minimum lease payments disclosed above.

As disclosed in Note 7 to our 2018 Annual Report under an Owner Participation Agreement (“OPA”) entered into by LandWell with the Redevelopment Agency of the City of Henderson, Nevada, as LandWell develops certain real property for commercial and residential purposes in its master planned community in Henderson, Nevada, and the cost of certain public infrastructure may be reimbursed to LandWell through tax increment.

Prior to 2018, due to the significant uncertainty of the timing and amount of any of such potential tax increment reimbursements, we recognized any such tax increment reimbursements only when received. However, due to growth in the master planned community and the increase in tax increment funds to which LandWell is entitled, we determined in the first quarter of 2018 the tax increment reimbursements expected to be collected in the future would at least be sufficient to support recognizing the promissory note payable issued by the City of Henderson to LandWell. During the first quarter of 2018, we recognized $3.8 million of other income related to the existing promissory note and accrued interest as of January 1, 2018. During the first quarter of 2019, we received approval for additional tax increment reimbursement of $1.1 million, which was recognized as other income and is evidenced by a promissory note issued to LandWell by the City of Henderson. See Note 12.