Property, net:

Property, net consists of the following:



	September 30, 2018			December 31, 2017
Land	$	1,521,252		$	1,567,152
Buildings and improvements	6,308,628			6,385,035
Tenant improvements	659,402			620,352
Equipment and furnishings	186,377			187,998
Construction in progress	176,976			366,996
	8,852,635			9,127,533
Less accumulated depreciation	(2,031,597		)	(2,018,303		)
	$	6,821,038		$	7,109,230

Depreciation expense was $69,237 and $69,343 for the three months ended September 30, 2018 and 2017, respectively, and $204,031 and $207,663 for the nine months ended September 30, 2018 and 2017, respectively.

The gain (loss) on sale or write down of assets, net was $46,516 and $(11,854) for the three months ended September 30, 2018 and 2017, respectively, and $(514) and $37,234 for the nine months ended September 30, 2018 and 2017, respectively.

The gain (loss) on sale or write down of assets, net for the three and nine months ended September 30, 2018 includes a gain of $46,242 on the sale of a 75% ownership interest in Westside Pavilion (See Note 4—Investments in Unconsolidated Joint Ventures). The gain (loss) on sale or write down of assets, net for the nine months ended September 30, 2018 also includes a loss of $311 on the sale of Promenade at Casa Grande (See Note 15—Dispositions). The gain (loss) on sale or write down of assets, net for the nine months ended September 30, 2017 includes a gain of $59,698 on the sale of Cascade Mall and Northgate Mall (See Note 15—Dispositions) offset in part by a loss of $10,138 on the write down of an investment in non-real estate assets.

The gain (loss) on sale or write down of assets, net for the nine months ended September 30, 2018 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. The gain (loss) on sale or write down of assets, net for the three and nine months ended September 30, 2017 includes an impairment loss of $12,036 on Southridge Center. The impairment losses were due to the reduction of the estimated holding period of the properties.

The following table summarizes certain of the Company's assets that were measured on a nonrecurring basis as a result of 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
	Total Fair Value Measurement		(Level 1)		(Level 2)		(Level 3)
September 30, 2018	$	72,700	$	—	$	72,700	$	—

The fair values relating to the impairments were based on sales contracts.