Acquisitions - Summary of Fair Value Assets and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Feb. 28, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Cash	$ 203,864	$ 152,154		$ 99,699	$ 89,785
Goodwill	87,543	$ 51,786
Mainstream Energy Corporation
Business Acquisition [Line Items]
Cash	5,440
Accounts receivable	8,881
Inventory	23,886
Prepaid expenses	2,028
Property and equipment	6,113
Intangible assets	15,380
Other long-term assets	200
Accounts payable and accrued liabilities	(24,975)
Deferred revenue	(768)
Capital lease obligation	(2,869)
Other liabilities	(1,509)
Deferred tax liabilities	(4,843)
Indentifiable assets and liabilities assumed	26,964
Goodwill	51,786
Total	78,750		$ 78,800
Clean Energy Experts, LLC
Business Acquisition [Line Items]
Cash	424
Accounts receivable	639
Intangible assets	13,290
Accounts payable and accrued liabilities	(1,247)
Deferred tax liabilities	(5,146)
Indentifiable assets and liabilities assumed	7,960
Goodwill	35,757
Total	$ 43,717