Annual report pursuant to Section 13 and 15(d)

Business Segment Information - Segment Information (Details)

v3.22.0.1
Business Segment Information - Segment Information (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Segment Reporting Information [Line Items]      
Revenues $ 1,215,697 $ 1,032,275 $ 866,933
(Gain) loss on derivatives 240 (705) (1,068)
Net interest expense 14,548 13,347 13,166
Depreciation and intangible asset amortization 44,756 40,137 37,709
Income before taxes, excluding unallocated corporate activity 126,561 96,616 70,741
U.S. Regions      
Segment Reporting Information [Line Items]      
Revenues 528,293 404,152 369,248
U.S. Federal      
Segment Reporting Information [Line Items]      
Revenues 392,948 377,882 287,426
Canada      
Segment Reporting Information [Line Items]      
Revenues 49,457 47,797 37,919
Non-Solar DG      
Segment Reporting Information [Line Items]      
Revenues 137,243 106,417 84,683
All Other      
Segment Reporting Information [Line Items]      
Revenues 107,756 96,027 87,657
Operating Segments | U.S. Regions      
Segment Reporting Information [Line Items]      
Revenues 528,293 404,152 369,248
(Gain) loss on derivatives (1,017) (744) (890)
Net interest expense 6,255 6,392 6,582
Depreciation and intangible asset amortization 16,057 12,627 10,318
Income before taxes, excluding unallocated corporate activity 40,051 28,339 18,536
Operating Segments | U.S. Federal      
Segment Reporting Information [Line Items]      
Revenues 392,948 377,882 287,426
(Gain) loss on derivatives 0 0 0
Net interest expense 1,294 1,694 623
Depreciation and intangible asset amortization 4,666 3,945 3,427
Income before taxes, excluding unallocated corporate activity 52,386 44,560 40,553
Operating Segments | Canada      
Segment Reporting Information [Line Items]      
Revenues 49,457 47,797 37,919
(Gain) loss on derivatives (73) 153 0
Net interest expense 879 699 691
Depreciation and intangible asset amortization 1,872 1,580 1,397
Income before taxes, excluding unallocated corporate activity 1,584 2,560 562
Operating Segments | Non-Solar DG      
Segment Reporting Information [Line Items]      
Revenues 137,243 106,417 84,683
(Gain) loss on derivatives 1,330 (114) (178)
Net interest expense 5,793 4,467 5,338
Depreciation and intangible asset amortization 21,080 20,717 21,359
Income before taxes, excluding unallocated corporate activity 26,345 13,040 3,813
Operating Segments | All Other      
Segment Reporting Information [Line Items]      
Revenues 107,756 96,027 87,657
(Gain) loss on derivatives 0 0 0
Net interest expense 327 95 (68)
Depreciation and intangible asset amortization 1,081 1,268 1,208
Income before taxes, excluding unallocated corporate activity 6,195 8,117 7,277
Consolidation, Eliminations      
Segment Reporting Information [Line Items]      
Unallocated corporate activity $ (48,417) $ (40,188) $ (34,188)