Property, net:

Property, net consists of the following:



	March 31, 2018			December 31, 2017
Land	$	1,527,460		$	1,567,152
Buildings and improvements	6,164,004			6,385,035
Tenant improvements	616,955			620,352
Equipment and furnishings	183,434			187,998
Construction in progress	391,222			366,996
	8,883,075			9,127,533
Less accumulated depreciation	(1,974,659		)	(2,018,303		)
	$	6,908,416		$	7,109,230

Depreciation expense was $67,944 and $68,956 for the three months ended March 31, 2018 and 2017, respectively.

The (loss) gain on sale or write down of assets, net was $(37,512) and $49,565 for the three months ended March 31, 2018 and 2017, respectively.

The loss on sale or write down of assets, net for the three months ended March 31, 2018 includes an impairment loss of $36,338 on SouthPark Mall and $1,043 on Promenade at Casa Grande. The impairment losses are due to the reduction of the estimated holding period of the properties. The gain on sale or write down of assets, net for the three months ended March 31, 2017 includes a gain of $59,713 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 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 three months ended March 31, 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)
2018	$	49,000	$	—	$	49,000	$	—

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