Operations by Business Segment and Geographic Information Operations by Busines Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013		Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2012		Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Number of Reportable Segments													2
Revenues													$ 713,848		$ 680,153		$ 646,034
Income (loss) from operations	8,687		14,881	23,230	(6,009)	13,337		14,652	17,270	508			40,789		45,767		32,801
Interest expense													(2,708)		(2,698)		(3,794)
Interest income													311		200		43
Litigation settlement											(2,900)		0		0		(2,900)
Other													(2,827)		(2,611)		(2,850)
Income before income taxes													35,565		40,658		23,300
Depreciation													38,231		37,365		37,818
Amortization													1,980		1,742		1,908
Capital expenditures													45,205		29,734		34,701
Segment assets, total	333,378					330,932					303,734		333,378		330,932		303,734
Utility Services
Segment Reporting Information [Line Items]
Revenues													376,520		375,300		363,365
Income (loss) from operations													16,070		20,107		13,541
Depreciation													22,261		22,844		23,734
Amortization													359		465		466
Capital expenditures													21,642		15,737		17,241
Segment assets, total	145,021					150,294					137,689		145,021		150,294		137,689
Residential Commercial Services
Segment Reporting Information [Line Items]
Revenues													334,878		303,420		280,938
Income (loss) from operations													33,566		30,787		24,243
Depreciation													13,286		12,236		12,157
Amortization													1,440		1,058		1,039
Capital expenditures													17,577		10,266		13,362
Segment assets, total	122,542					122,298					105,552		122,542		122,298		105,552
All Other
Segment Reporting Information [Line Items]
Revenues													2,450		1,433		1,731
Income (loss) from operations													(2,869)		(1,366)		1,342
Depreciation													0		0		0
Amortization													0		0		0
Capital expenditures													0		0		0
Segment assets, total	0					0					0		0		0		0
Reconciling Adjustments
Segment Reporting Information [Line Items]
Revenues													0		0		0
Income (loss) from operations													(5,978)	[1]	(3,761)	[1]	(6,325)	[1]
Interest expense													(2,708)		(2,698)		(3,794)
Interest income													311		200		43
Litigation settlement																	(2,900)
Other													(2,827)		(2,611)		(2,850)
Depreciation													2,684	[2]	2,285	[2]	1,927	[2]
Amortization													181		219		403
Capital expenditures													5,986		3,731		4,098
Segment assets, total	$ 65,815	[3]				$ 58,340	[3]				$ 60,493	[3]	$ 65,815	[3]	$ 58,340	[3]	$ 60,493	[3]

[1] Reconciling adjustments from segment reporting to consolidated external financial reporting include reclassification of depreciation expense and allocation of corporate expenses.

[2] Adjustments to declining-balance method depreciation expense from straight-line method and depreciation and amortization of corporate assets.

[3] Corporate assets include cash, prepaid expenses, corporate facilities, enterprise-wide information systems and other nonoperating assets.