PROPERTY AND EQUIPMENT.

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT.

5. PROPERTY AND EQUIPMENT.

Property and equipment consisted of the following (in thousands):

	December 31,
	2018			2017
Facilities and plant equipment	$	621,909		$	601,156
Land		8,970			8,970
Other equipment, vehicles and furniture		11,812			10,189
Construction in progress		30,312			38,041
		673,003			658,356
Accumulated depreciation		(190,346	)		(150,004	)
	$	482,657		$	508,352

Depreciation expense was $40,849,000, $38,651,000 and $35,441,000 for the years ended December 31, 2018, 2017 and 2016, respectively.

For the year ended December 31, 2018, 2017 and 2016, the Company capitalized interest of $1,170,000, $822,000 and $1,307,000, respectively, related to its capital investment activities.