Operations by Business Segment and Geographic Information Operations by business segment (Tables)

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Schedule of segment reporting information, by segment [Table Text Block]

Information on reportable segments and reconciliation to the consolidated financial statements follows: 

	Utility Services		Residential Commercial Services		All Other			Reconciling  Adjustments				Consolidated
Fiscal Year 2018
Revenues	$	537,484	$	486,005	$	1,302		$	—			$	1,024,791
Income (loss) from operations	32,370		47,812		(19,816		)	(4,676		)	(a)	55,690
Interest expense								(7,039		)		(7,039		)
Interest income								350				350
Other income (expense), net								(11,505		)		(11,505		)
Income before income taxes												$	37,496
Depreciation	$	29,526	$	21,720	$	—		$	3,668		(b)	$	54,914
Amortization	211		1,842		—			2				2,055
Capital expenditures	32,148		22,256		—			6,006				60,410
Segment assets, total	239,426		208,369		—			78,828			(c)	526,623
Fiscal Year 2017
Revenues	$	466,727	$	446,028	$	3,203		$	—			$	915,958
Income (loss) from operations	18,223		41,158		(2,634		)	(4,556		)	(a)	52,191
Interest expense								(4,886		)		(4,886		)
Interest income								292				292
Other income (expense), net								(9,603		)		(9,603		)
Income before income taxes												$	37,994
Depreciation	$	27,928	$	19,384	$	—		$	3,390		(b)	$	50,702
Amortization	122		2,240		—			22				2,384
Capital expenditures	26,910		23,199		—			6,991				57,100
Segment assets, total	189,662		197,698		—			85,775			(c)	473,135
Fiscal Year 2016
Revenues	$	433,379	$	410,878	$	1,421		$	—			$	845,678
Income (loss) from operations	19,256		36,640		(4,318		)	(2,711		)	(a)	48,867
Interest expense								(4,393		)		(4,393		)
Interest income								255				255
Other income (expense), net								(7,485		)		(7,485		)
Income before income taxes												$	37,244
Depreciation	$	26,855	$	17,198	$	—		$	3,231		(b)	$	47,284
Amortization	135		2,136		—			35				2,306
Capital expenditures	28,660		21,819		—			6,167				56,646
Segment assets, total	171,220		166,858		—			85,861			(c)	423,939

Schedule of revenue from external customers and long-lived assets attributed to foreign countries by geographic area [Table Text Block]

Geographic Information--The following presents revenues and long-lived assets by geographic territory:

	Year Ended December 31,
	2018		2017		2016
Revenues
United States	$	949,317	$	847,540	$	775,870
Canada	75,474		68,418		69,808
	$	1,024,791	$	915,958	$	845,678
	December 31,
	2018		2017		2016
Long-lived assets, net
United States	$	251,181	$	242,118	$	224,727
Canada	20,374		21,893		20,439
	$	271,555	$	264,011	$	245,166