
	September 30, 2019		December 31, 2018
Land	$	1,508,445	$	1,506,678
Buildings and improvements	6,315,465		6,288,308
Tenant improvements	708,230		678,110
Equipment and furnishings(1)	214,065		206,398
Construction in progress	204,172		199,326
	8,950,377		8,878,820
Less accumulated depreciation(1)	(2,286,271)		(2,093,044)
	$	6,664,106	$	6,785,776

(1) Equipment and furnishings and accumulated depreciation include the cost and accumulated amortization of ROU assets in connection with finance leases at September 30, 2019 (See Note 8—Leases).

Depreciation expense was $72,519 and $69,237 for the three months ended September 30, 2019 and 2018, respectively, and $214,689 and $204,031 for the nine months ended September 30, 2019 and 2018, respectively.

The (loss) gain on sale or write down of assets, net for the three and nine months ended September 30, 2019 and 2018 consist of the following:


	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2019		2018		2019		2018
Property sales(1)	$	—	$	46,242	$	—	$	45,931
Write-down of assets(2)	(212)		(1,786)		(16,121)		(50,578)
Land sales	81		2,060		615		4,133
	$	(131)	$	46,516	$	(15,506)	$	(514)

(1) Gain on sale of properties during the three and nine months ended September 30, 2018 includes a gain of $46,242 on the sale of a 75% ownership interest in One Westside (See Note 4—Investments in Unconsolidated Joint Ventures). Gain on sale of properties during the nine months ended September 30, 2018 also includes the loss of $311 on the sale of Promenade at Casa Grande (See Note 16—Dispositions).

(2) Includes impairment losses of $36,338 on SouthPark Mall, $7,494 on two freestanding stores, $1,695 on Southridge Center and $1,043 on Promenade at Casa Grande during the nine months ended September 30, 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.

The following table summarizes certain of the Company's assets that were measured on a nonrecurring basis as a result of the impairment losses recorded for the nine months ended September 30, 2018, as described above:


	Total Fair Value Measurement		Quoted Prices in Active Markets for Identical Assets		Significant Other Unobservable Inputs		Significant Unobservable Inputs
					(Level 1)		(Level 2)		(Level 3)
September 30, 2018	$	72,700	$	—	$	72,700	$	—