Our portfolio of nonmineral leases is composed of leases for real estate (including office buildings, aggregates sales yards, and concrete and asphalt sites) and equipment (including railcars and rail track, barges, office equipment and plant equipment).

Lease right-of-use (ROU) assets and liabilities reflected on our December 31 balance sheets and the weighted-average lease term and discount rate are as follows:



in thousands	Classification on the Balance Sheet	2020	2019
Assets
Operating lease ROU assets	Operating lease right-of-use assets, net	$ 482,513	$ 441,656
Accumulated amortization		(59,385)	(33,467)
Finance lease assets	Property, plant & equipment, net	7,796	1,226
Accumulated amortization		(1,640)	(65)
Total lease assets		$ 429,284	$ 409,350
Liabilities
Current
Operating	Other current liabilities	$ 36,969	$ 29,971
Finance	Other current liabilities	2,047	430
Noncurrent
Operating	Operating lease liabilities	399,582	388,042
Finance	Other noncurrent liabilities	4,139	733
Total lease liabilities		$ 442,737	$ 419,176
Lease Term and Discount Rate
Weighted-average remaining lease term (years)
Operating leases		9.5	9.9
Finance leases		4.2	2.8
Weighted-average discount rate
Operating leases		3.6%	4.3%
Finance leases		1.4%	3.0%

Our building leases have remaining noncancelable periods of 0 - 7 years and lease terms (including options to extend) of 0 - 26 years. Key factors in determining the certainty of lease renewals include the location of the building, the value of leasehold improvements and the cost to relocate. Rental payments for certain of our building leases are periodically adjusted for inflation, and this variable component is recognized as expense when incurred. Many of our building leases contain common area maintenance charges which we include in the calculation of our lease liability (the lease consideration is not allocated between the lease and non-lease components).

Our aggregates sales yard leases have remaining noncancelable periods of 0 - 28 years and lease terms of 0 - 78 years. The key factor in determining the certainty of lease renewals is the financial impact of extending the lease, including the reserve life of the sourcing aggregates quarry. Certain aggregates sales yard lease agreements include rental payments based on a percentage of sales over contractual levels or the number of shipments received into the sales yard. Variable payments for these sales yards comprise a majority of the overall variable lease cost presented in the table below.

Our concrete and asphalt site leases have remaining noncancelable periods of 0 - 19 years and lease terms of 1 - 78 years. The key factor in determining the certainty of lease renewals is the financial impact of extending the lease, including the reserve life of the sourcing aggregates quarry. Rental payments are generally fixed for our concrete and asphalt sites.

Our rail (car and track) leases have remaining noncancelable periods of 0 - 4 years and lease terms of 2 - 64 years. Key factors in determining the certainty of lease renewals include the market rental rate for comparable assets and, in some cases, the cost incurred to restore the asset. Rental payments are fixed for our rail leases. The majority of our rail leases contain substitution rights that allow the supplier to replace damaged equipment. Because these rights are generally limited to either replacing railcars or moving our placement on rail track for purposes of repair or maintenance, we do not consider these substitution rights to be substantive and have recorded a lease liability and ROU asset for all leased rail.

Our barge leases have remaining noncancelable periods of 0 - 1 years and lease terms of 0 - 14 years. Key factors in determining the certainty of lease renewals include the market rental rate for comparable assets and, in some cases, the cost incurred to restore the asset. Rental payments are fixed. Like our rail leases, our barge leases contain non-substantive substitution rights that are limited to replacing barges in need of repair or maintenance.

Office and plant equipment leases have remaining noncancelable periods of 0 - 5 years and lease terms of 0 - 5 years. The key factor in determining the certainty of lease renewals is the market rental rate for comparable assets. Rental payments are generally fixed for our equipment leases with terms greater than 1 year. The significant majority of our short-term lease cost presented in the table below is derived from office and plant equipment leases with terms of 1 year or less.

Our lease agreements do not contain residual value guarantees, restrictive covenants or early termination options that we deem material. We have not sought or been granted any material lease concessions as a result of the COVID-19 pandemic.

The components of lease expense for the years ended December 31, 2020 and 2019 are as follows:



in thousands	2020	2019
Lease Cost
Finance lease cost
Amortization of right-of-use assets	$ 1,616	$ 64
Interest on lease liabilities	(102)	(4)
Operating lease cost	58,489	56,546
Short-term lease cost ¹	30,508	35,427
Variable lease cost	12,885	13,739
Sublease income	(2,682)	(3,108)
Total lease cost	$ 100,714	$ 102,664

Cash paid for operating leases was $54,871,000 for 2020 and $52,660,000 for 2019. Cash paid for finance leases was $102,000 for 2020 and $4,000 for 2019.

Maturity analysis on an undiscounted basis of our lease liabilities (see Note 12 for mineral lease payments) as of December 31, 2020 is as follows:



	Operating	Finance
in thousands	Leases	Leases
Maturity of Lease Liabilities
2021	$ 54,733	$ 2,134
2022	48,225	1,986
2023	41,206	1,058
2024	36,141	779
2025	36,375	349
Thereafter	565,042	50
Total minimum lease payments	$ 781,722	$ 6,356
Less: Lease payments representing interest	345,171	170
Present value of future minimum lease payments	$ 436,551	$ 6,186
Less: Current obligations under leases	36,969	2,047
Long-term lease obligations	$ 399,582	$ 4,139