We report as discontinued operations properties which met the criteria to be accounted for as held for sale in accordance with GAAP as of June 30, 2014, and certain properties disposed of during the periods presented that were previously classified as held for sale as of June 30, 2014. All results of these discontinued operations are included in a separate component of income on the consolidated statements of operations under the caption discontinued operations.

During the year ended December 31, 2018, we sold nine properties, in separate transactions that did not meet the criteria to be classified as discontinued operations, which resulted in an aggregate gain of $3,888,000, included in gain on dispositions of real estate, on our consolidated statements of operations. We also received funds from property condemnations resulting in a gain of $60,000, included in gain on dispositions of real estate, on our consolidated statements of operations.

During the year ended December 31, 2017, we sold 12 properties and a portion of one property, in separate transactions that did not meet the criteria to be classified as discontinued operations, which resulted in an aggregate gain of $1,025,000, included in gain on dispositions of real estate, on our consolidated statements of operations. We also received funds from property condemnations resulting in a gain of $16,000, included in gain on dispositions of real estate, on our consolidated statements of operations.

As of December 31, 2018 and 2017, there were no properties that met criteria to be classified as held for sale.

	Year ended December 31,
	2018			2017			2016
Total revenues	$	—		$	—		$	—
Impairments		(1,268	)		(1,042	)		(4,248	)
Changes in environmental estimates		564			3,169			3,010
Other operating income		—			11			2
Earnings (loss) from operating activities		(704	)		2,138			(1,236	)
(Loss) gains from dispositions of real estate		—			—			(178	)
Earnings (loss) from discontinued operations	$	(704	)	$	2,138		$	(1,414	)