Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 159,981	$ 133,752	$ 310,747	$ 270,088
Cost of Services	132,169	112,044	255,302	225,676
Gross Profit	27,812	21,708	55,445	44,412
Selling, General and Administrative Expense	24,267	19,409	46,778	38,107
Contingent Consideration Expense	266	0	266	0
Loss on sale of assets	775	1	776	7
Operating Income	2,504	2,298	7,625	6,298
Depreciation and amortization	1,031	589	1,848	1,169
Capital Expenditures	732	927	1,084	1,626
Assets	235,779	201,108	235,779	201,108	$ 226,710
Communications [Member]
Segment Reporting Information [Line Items]
Revenues	39,351	27,945	80,111	59,753
Cost of Services	32,767	23,170	65,369	49,680
Gross Profit	6,584	4,775	14,742	10,073
Selling, General and Administrative Expense	4,979	3,424	9,692	7,102
Loss on sale of assets	0	0	0	7
Operating Income	1,605	1,351	5,050	2,964
Depreciation and amortization	135	129	257	246
Capital Expenditures	479	278	564	470
Assets	41,753	27,499	41,753	27,499
Residential [Member]
Segment Reporting Information [Line Items]
Revenues	53,387	50,169	105,514	98,762
Cost of Services	40,616	40,503	81,071	79,908
Gross Profit	12,771	9,666	24,443	18,854
Selling, General and Administrative Expense	8,906	7,731	17,620	15,032
Loss on sale of assets	0	4	0	4
Operating Income	3,865	1,931	6,823	3,818
Depreciation and amortization	121	119	242	242
Capital Expenditures	102	124	144	193
Assets	38,088	37,898	38,088	37,898
Commercial & Industrial [Member]
Segment Reporting Information [Line Items]
Revenues	54,146	44,505	99,410	88,272
Cost of Services	48,946	39,686	89,354	78,169
Gross Profit	5,200	4,819	10,056	10,103
Selling, General and Administrative Expense	4,603	3,791	8,242	7,378
Loss on sale of assets	0	(1)	0	(2)
Operating Income	597	1,029	1,814	2,727
Depreciation and amortization	252	67	434	135
Capital Expenditures	37	159	185	167
Assets	48,139	46,793	48,139	46,793
Infrastructure Solutions [Member]
Segment Reporting Information [Line Items]
Revenues	13,097	11,133	25,712	23,301
Cost of Services	9,840	8,685	19,508	17,919
Gross Profit	3,257	2,448	6,204	5,382
Selling, General and Administrative Expense	3,115	2,313	5,814	4,332
Contingent Consideration Expense	266	0	266	0
Loss on sale of assets	775	(2)	776	(2)
Operating Income	(899)	137	(652)	1,052
Depreciation and amortization	455	204	779	405
Capital Expenditures	114	366	191	657
Assets	33,610	28,292	33,610	28,292
Corporate [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Cost of Services	0	0	0	0
Gross Profit	0	0	0	0
Selling, General and Administrative Expense	2,664	2,150	5,410	4,263
Loss on sale of assets	0	0	0	0
Operating Income	(2,664)	(2,150)	(5,410)	(4,263)
Depreciation and amortization	68	70	136	141
Capital Expenditures	0	0	0	139
Assets	$ 74,189	$ 60,626	$ 74,189	$ 60,626