Annual report pursuant to Section 13 and 15(d)

Preliminary Values Assigned to Assets Acquired and Liabilities Assumed (Detail)

Preliminary Values Assigned to Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Apr. 17, 2014	Dec. 31, 2013	Mar. 08, 2013	Dec. 31, 2012	Nov. 15, 2013	Aug. 22, 2013
Business Acquisition [Line Items]
Goodwill	$ 42,991us-gaap_Goodwill	$ 18,600us-gaap_Goodwill	$ 21,498us-gaap_Goodwill		$ 10,166us-gaap_Goodwill
Intangible assets		20,000		1,599
Purchase price				856
Tri-State DE LLC
Business Acquisition [Line Items]
Accounts receivable						468
Inventory						310
Goodwill						2,786
Other intangibles						738
Other assets						38
Assets acquired						6,500
Accounts payable						440
Accrued liabilities						208
Other current liabilities						80
Liabilities assumed						728
Purchase price						5,772
Tri-State DE LLC \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets						1,680
Tri-State DE LLC \| Non-compete agreements
Business Acquisition [Line Items]
Intangible assets						480
Value Lighting
Business Acquisition [Line Items]
Cash		35
Accounts receivable		8,720
Inventory		7,505
Goodwill		18,635
Other intangibles		116
Other assets		2,901
Assets acquired		57,747
Accounts payable		8,683
Accrued liabilities		1,383
Other current liabilities		1,362
Other liabilities		1,185
Deferred income tax liability		5,825
Liabilities assumed		18,438
Purchase price		39,309
Value Lighting \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets		12,270
Value Lighting \| Non-compete agreements
Business Acquisition [Line Items]
Intangible assets		260
Value Lighting \| Backlog
Business Acquisition [Line Items]
Intangible assets		2,505
Value Lighting \| Trade Names
Business Acquisition [Line Items]
Intangible assets		4,800
Relume Technologies Inc
Business Acquisition [Line Items]
Cash							61
Accounts receivable							851
Inventory							1,935
Goodwill							8,624
Other assets							838
Assets acquired							16,209
Accounts payable							2,574
Accrued liabilities							1,891
Other current liabilities							26
Capital lease obligations							110
Liabilities assumed							4,601
Purchase price							11,608
Relume Technologies Inc \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets							680
Relume Technologies Inc \| Trademarks
Business Acquisition [Line Items]
Intangible assets							1,200
Relume Technologies Inc \| Technology
Business Acquisition [Line Items]
Intangible assets							2,020
Seesmart Technologies Incorporated
Business Acquisition [Line Items]
Cash	69
Accounts receivable	1,048
Inventory	1,352
Goodwill	10,166
Other assets	334
Assets acquired	23,676
Accounts payable	2,692
Accrued liabilities	1,137
Deferred revenue	104
Liabilities assumed	5,400
Purchase price	18,276
Seesmart Technologies Incorporated \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets	7,273
Seesmart Technologies Incorporated \| Trademarks
Business Acquisition [Line Items]
Intangible assets	3,434
Seesmart Technologies Incorporated \| Customer Deposits
Business Acquisition [Line Items]
Other current liabilities	$ 1,467