OTHER NON-OPERATING INCOME (EXPENSE)

A summary of non-operating income (expense) is as follows:



	Year Ended December 31
(in thousands)	2018			2017			2016
Loss on guarantor obligations	$	(17,518	)	$	—		$	—
Net gain on cost method investments	11,663			—			—
Net gain (loss) on sales of businesses	8,157			(569		)	18,931
Foreign currency (loss) gain, net	(3,844		)	3,310			(39,890		)
Gain on sale of cost method investments	2,845			16			794
Impairment of cost method investments	(2,697		)	(200		)	(29,365		)
Net gain on sale of property, plant and equipment	2,539			—			34,072
Gain on formation of a joint venture	—			—			3,232
Net losses on sales or write-down of marketable equity securities	—			—			(1,791		)
Other, net	958			1,684			1,375
Total Other Non-Operating Income (Expense)	$	2,103		$	4,241		$	(12,642	)

In 2018, the Company recorded a $17.5 million loss in guarantor lease obligations in connection with the sale of the KHE Campuses business.

In the third quarter of 2018, the Company recorded an $8.5 million gain resulting from observable price changes in the fair value of equity securities accounted for under the cost method. In the fourth quarter of 2018, an additional $3.2 million gain was recorded.

In 2018, the Company recorded an $8.2 million gain on the sale of three businesses in the education division, including a gain of $4.3 million on the Kaplan University transaction and $1.9 million in contingent consideration gains related to the sale of a business (see Note 3).

In the third quarter of 2016, the Company recorded an impairment of $15.0 million to the preferred equity interest in a vocational school company. In the fourth quarter of 2016, an additional $12.0 million impairment was recorded.

In the second quarter of 2016, the Company sold the remaining portion of the Robinson Terminal real estate retained from the sale of the Publishing Subsidiaries, for a gain of $34.1 million.

In June 2016, GHG contributed assets to a joint venture entered into with a Michigan hospital in exchange for a 40% equity interest and other assets, resulting in a $3.2 million gain (see Note 3). The Company used an income and market approach to value the equity interest. The measurement of the equity interest in the joint venture is classified as a Level 3 fair value assessment due to the significance of unobservable inputs developed in the determination of the fair value.

In the first quarter of 2016, Kaplan sold Colloquy, which was part of Kaplan corporate and other, for a gain of $18.9 million.