5.	PROPERTY, PLANT AND EQUIPMENT

	Estimated Useful	December 31,			September 30,
	Lives (Years)	2018			2019
		(dollars in thousands)
Land	N/A	$	24,705		$	24,705
Land improvements	10-20		5,758			5,804
Pipelines and facilities	5-30		116,155			118,449
Storage and terminal facilities	10-35		321,096			326,738
Transportation equipment	3-10		2,798			3,140
Office property and equipment and other	3-20		26,980			27,415
Pipeline linefill and tank bottoms	N/A		10,297			8,258
Construction-in-progress	N/A		4,026			3,077
Property, plant and equipment, gross			511,815			517,586
Accumulated depreciation			(263,554	)		(278,768	)
Property, plant and equipment, net		$	248,261		$	238,818

Property, plant and equipment under operating leases at

September 30, 2019

, in which the Partnership is the lessor, had a cost basis of

$285.3

million and accumulated depreciation of

$178.6

million.

Depreciation expense for the

three

months ended

September 30, 2018

and

2019

, was

$6.5

million and

$5.5

million, respectively. Depreciation expense for the

nine

months ended

September 30, 2018

and

2019

, was

$20.2

million and

$16.9

million, respectively.

During the

nine

months ended

September 30, 2019

, the Partnership recognized asset impairment expense of

$2.3

million. A change in estimate of the push-down impairment related to Cimarron Express Pipeline, LLC (“Cimarron Express”) resulted in additional impairment expense of

$2.0

million. This impairment is recorded at the corporate level and the estimate is based on the expected amount due to Ergon, Inc. (“Ergon”) if the Put (as defined in Note

) is exercised (see Note

for more information). In addition, flooding at several asphalt plants in the Midwest led to an impairment of

$0.3

million.

During the

nine

months ended

September 30, 2019

, the Partnership sold various surplus assets, including the sale of

three

truck stations for

$1.6

million, which resulted in a gain of

$1.5

million, and the sale of pipeline linefill for

$1.6

million, which resulted in a gain of

$0.3

million. In addition, proceeds received during the

nine

months ended

September 30, 2019

, included

$2.6

million related to a sale of pipeline linefill in

December 2018

for which the proceeds were received in

January 2019.

July 12, 2018,

the Partnership sold certain asphalt terminals, storage tanks and related real property, contracts, permits, assets and other interests located in Lubbock and Saginaw, Texas and Memphis, Tennessee (the “Divestiture”) to Ergon Asphalt & Emulsion, Inc. for a purchase price of

$90.0

million, subject to customary adjustments. The Divestiture does

not

qualify as discontinued operations as it does

not

represent a strategic shift that will have a major effect on the Partnership’s operations or financial results. The Partnership used the proceeds from the sale to prepay revolving debt under its credit agreement.

April 2018,

the Partnership sold its producer field services business. The Partnership received cash proceeds at closing of approximately

$3.0

million and recorded a gain of

$0.4

million. The sale of the producer field services business does

not

qualify as discontinued operations as it does

not

March 2018,

the Partnership acquired an asphalt terminalling facility in Oklahoma from a

third

party for approximately

$22.0

million, consisting of property, plant and equipment of

$11.5

million, intangible assets of

$7.6

million and goodwill of

$2.9

million.