Property, net:
Property, net at December 31, 2020 and 2019 consists of the following:
| | | | | | | | | | | |
| 2020 | | 2019 |
| Land | $ | 1,538,270 | | | $ | 1,520,678 | |
| Buildings and improvements | 6,620,708 | | | 6,389,458 | |
| Tenant improvements | 750,250 | | | 726,533 | |
| Equipment and furnishings(1) | 194,231 | | | 230,215 | |
| Construction in progress | 153,253 | | | 126,165 | |
| 9,256,712 | | | 8,993,049 | |
| Less accumulated depreciation | (2,562,133) | | | (2,349,536) | |
| $ | 6,694,579 | | | $ | 6,643,513 | |
(1)Equipment and furnishings and accumulated depreciation include the cost and accumulated amortization of ROU assets in connection with finance leases at December 31, 2020 and 2019 (See Note 8—Leases).
Depreciation expense for the years ended December 31, 2020, 2019 and 2018 was $287,925, $287,846 and $275,236, respectively.
The (loss) gain on sale or write down of assets, net for the years ended December 31, 2020, 2019 and 2018 consist of the following:
| | | | | | | | | | | | | | | | | |
| 2020 | | 2019 | | 2018 |
| Property sales(1) | $ | — | | | $ | — | | | $ | 45,931 | |
| Write-down of assets(2) | (76,705) | | | (16,285) | | | (82,745) | |
| Land sales(3) | 8,593 | | | 4,376 | | | 4,989 | |
| | | | | |
| $ | (68,112) | | | $ | (11,909) | | | $ | (31,825) | |
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(1)Property sales during the year ended December 31, 2018 includes a $46,242 gain on the sale of a 75% ownership interest in One Westside (See Note 4—Investments in Unconsolidated Joint Ventures) and a loss of on the sale of $311 on the sale of Promenade at Casa Grande (See Note 17—Dispositions).
(2)Includes impairment losses of $30,063 on Wilton Mall, $6,640 on Paradise Valley Mall and $4,154 on the write-down of non-real estate assets during the year ended December 31, 2020 and $36,338 on Southpark Mall, $7,907 on La Cumbre Plaza, $7,494 on two freestanding stores, $1,697 on Southridge Center and $1,043 on Promenade at Casa Grande during the year ended December 31, 2018. The impairment losses were due to the reduction of the estimated holding periods of the properties. The remaining balances represent the write off of development costs in 2020, 2019 and 2018.
(3)Includes impairment losses of $5,047 for undeveloped land that is currently under contract for sale as of December 31, 2020.
The following table summarizes certain of the Company's assets that were measured on a nonrecurring basis as a result of impairment charges recorded for the years ended December 31, 2020 and 2018 as described above:
| | | | | | | | | | | | | | | | | | | | | | | | | | |
| Years ended December, 31 | | Total Fair Value Measurement | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs |
| | (Level 1) | | (Level 2) | | (Level 3) |
| 2020 | | $ | 151,875 | | | $ | — | | | $ | 151,875 | | | $ | — | |
| 2018 | | $ | 104,700 | | | $ | — | | | 104,700 | | | $ | — | |
The fair value relating to impairments that were based on sales contracts were classified within Level 2 of the fair value hierarchy.