Quarterly report pursuant to Section 13 or 15(d)

Business Segment Information (Details)

v3.8.0.1
Business Segment Information (Details) - USD ($)
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Segment Reporting Information [Line Items]    
Revenues $ 167,410,000 $ 134,610,000
Interest income 56,000 19,000
Interest expense 2,997,000 1,848,000
Depreciation and amortization of intangible assets 6,734,000 5,747,000
Unallocated corporate activity 0  
Income (loss) before taxes, excluding unallocated corporate activity 11,595,000 4,497,000
Operating Segments | U.S. Regions    
Segment Reporting Information [Line Items]    
Revenues 74,691,000 44,489,000
Interest income 1,000 1,000
Interest expense 1,191,000 365,000
Depreciation and amortization of intangible assets 1,330,000 519,000
Income (loss) before taxes, excluding unallocated corporate activity 4,618,000 (2,500,000)
Operating Segments | U.S. Federal    
Segment Reporting Information [Line Items]    
Revenues 47,785,000 47,924,000
Interest income 20,000 6,000
Interest expense 241,000 267,000
Depreciation and amortization of intangible assets 672,000 653,000
Income (loss) before taxes, excluding unallocated corporate activity 5,817,000 5,445,000
Operating Segments | Canada    
Segment Reporting Information [Line Items]    
Revenues 8,904,000 9,501,000
Interest income 0 1,000
Interest expense 484,000 447,000
Depreciation and amortization of intangible assets 289,000 289,000
Income (loss) before taxes, excluding unallocated corporate activity (2,362,000) (513,000)
Operating Segments | Non-Solar DG    
Segment Reporting Information [Line Items]    
Revenues 18,117,000 15,646,000
Interest income 35,000 11,000
Interest expense 1,081,000 757,000
Depreciation and amortization of intangible assets 4,064,000 3,808,000
Income (loss) before taxes, excluding unallocated corporate activity 2,610,000 1,168,000
Operating Segments | All Other    
Segment Reporting Information [Line Items]    
Revenues 17,913,000 17,050,000
Interest income 0 0
Interest expense 0 12,000
Depreciation and amortization of intangible assets 379,000 478,000
Income (loss) before taxes, excluding unallocated corporate activity 912,000 897,000
Unallocated corporate activity    
Segment Reporting Information [Line Items]    
Unallocated corporate activity (6,869,000) (6,886,000)
Unallocated corporate activity | U.S. Regions    
Segment Reporting Information [Line Items]    
Unallocated corporate activity 0 0
Unallocated corporate activity | U.S. Federal    
Segment Reporting Information [Line Items]    
Unallocated corporate activity 0 0
Unallocated corporate activity | Canada    
Segment Reporting Information [Line Items]    
Unallocated corporate activity 0 0
Unallocated corporate activity | Non-Solar DG    
Segment Reporting Information [Line Items]    
Unallocated corporate activity 0 0
Unallocated corporate activity | All Other    
Segment Reporting Information [Line Items]    
Unallocated corporate activity $ 0 $ 0