Quarterly report pursuant to Section 13 or 15(d)

Business Segment Information (Details)

v3.10.0.1
Business Segment Information (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Segment Reporting Information [Line Items]        
Revenues $ 196,982,000 $ 166,665,000 $ 364,392,000 $ 301,275,000
Interest income 77,000 27,000 133,000 46,000
Interest expense 3,235,000 2,271,000 6,232,000 4,119,000
Depreciation and amortization of intangible assets 7,053,000 5,659,000 13,787,000 11,406,000
Unallocated corporate activity 0   0  
Income before taxes, excluding unallocated corporate activity 17,760,000 14,226,000 29,355,000 18,723,000
U.S. Regions        
Segment Reporting Information [Line Items]        
Revenues 88,778,000   163,469,000  
U.S. Federal        
Segment Reporting Information [Line Items]        
Revenues 58,214,000   105,999,000  
Canada        
Segment Reporting Information [Line Items]        
Revenues 7,958,000   16,862,000  
Non-Solar DG        
Segment Reporting Information [Line Items]        
Revenues 19,921,000   38,038,000  
All Other        
Segment Reporting Information [Line Items]        
Revenues 22,111,000   40,024,000  
Operating Segments | U.S. Regions        
Segment Reporting Information [Line Items]        
Revenues 88,778,000 64,834,000 163,469,000 109,323,000
Interest income 2,000 0 3,000 1,000
Interest expense 1,031,000 565,000 2,222,000 930,000
Depreciation and amortization of intangible assets 1,377,000 554,000 2,707,000 1,073,000
Income before taxes, excluding unallocated corporate activity 4,732,000 3,456,000 9,350,000 956,000
Operating Segments | U.S. Federal        
Segment Reporting Information [Line Items]        
Revenues 58,214,000 59,106,000 105,999,000 107,030,000
Interest income 28,000 9,000 48,000 15,000
Interest expense 247,000 266,000 488,000 533,000
Depreciation and amortization of intangible assets 661,000 654,000 1,333,000 1,307,000
Income before taxes, excluding unallocated corporate activity 10,078,000 8,881,000 15,895,000 14,326,000
Operating Segments | Canada        
Segment Reporting Information [Line Items]        
Revenues 7,958,000 8,991,000 16,862,000 18,492,000
Interest income 0 0 0 1,000
Interest expense 477,000 487,000 961,000 934,000
Depreciation and amortization of intangible assets 290,000 286,000 579,000 575,000
Income before taxes, excluding unallocated corporate activity (285,000) 614,000 (2,647,000) 101,000
Operating Segments | Non-Solar DG        
Segment Reporting Information [Line Items]        
Revenues 19,921,000 15,210,000 38,038,000 30,856,000
Interest income 47,000 18,000 82,000 29,000
Interest expense 1,467,000 940,000 2,548,000 1,697,000
Depreciation and amortization of intangible assets 4,348,000 3,733,000 8,412,000 7,541,000
Income before taxes, excluding unallocated corporate activity 2,335,000 859,000 4,945,000 2,027,000
Operating Segments | All Other        
Segment Reporting Information [Line Items]        
Revenues 22,111,000 18,524,000 40,024,000 35,574,000
Interest income 0 0 0 0
Interest expense 13,000 13,000 13,000 25,000
Depreciation and amortization of intangible assets 377,000 432,000 756,000 910,000
Income before taxes, excluding unallocated corporate activity 900,000 416,000 1,812,000 1,313,000
Unallocated corporate activity        
Segment Reporting Information [Line Items]        
Unallocated corporate activity $ (7,751,000) $ (7,206,000) $ (14,620,000) $ (14,092,000)