Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2018

Supplemental Cash Flow Information [Abstract]

Supplemental cash flow information [Table Text Block]

Supplemental cash flow information follows:

	Year Ended December 31,
Supplemental cash flow information	2018			2017			2016
Interest paid	$	6,375		$	5,096		$	4,329
Income taxes paid, net	11,514			10,005			10,578
Noncash transactions:
Debt issued for purchases of businesses	$	2,402		$	3,099		$	875
Detail of acquisitions:
Assets acquired:
Accounts receivable	$	1,311		$	1,753		$	—
Operating supplies	23			—			157
Prepaid expense	89			128			55
Equipment	4,079			1,904			2,485
Other assets	7			52			—
Intangible assets	4,895			4,296			1,374
Goodwill	2,840			5,131			817
Liabilities assumed	(2,381		)	(2,713		)	(216		)
Debt issued for purchases of businesses	(2,402		)	(3,099		)	(875		)
Cash paid	$	8,461		$	7,452		$	3,797