Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of Property and Equipment

Depreciation is computed using the straight-line method over the following estimated useful lives:

	Years
Buildings		10-40
Trucks and automotive equipment		3-10
Shop machinery and equipment		3-10
Land improvements		10-15
Rental equipment		5-10
Office equipment		3-10

Property and equipment consists of the following (in thousands):
	December 31,
	2017			2016
Land and land improvements	$	1,538		$	1,335
Buildings	5,394			5,265
Machinery and equipment	10,913			9,363
Rental equipment	2,763			1,972
	20,608			17,935
Less: accumulated depreciation and amortization	(10,741		)	(9,928		)
	$	9,867		$	8,007