Summary of Significant Accounting Policies - Recently Issued Accounting Pronouncements (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Net sales | $ 126,956 | $ 106,646 | $ 102,982 | $ 112,795 | $ 119,965 | $ 99,586 | $ 105,257 | $ 93,323 | $ 449,379 | $ 418,131 | $ 382,090 |
| Cost of Sales | 422,303 | 390,800 | 355,517 | ||||||||
| Gross profit | 7,502 | 6,244 | 6,572 | 6,758 | 8,006 | 6,372 | 7,000 | 5,953 | 27,076 | 27,331 | 26,573 |
| Income from operations | 7,813 | 8,616 | 8,510 | ||||||||
| Net Income | 5,062 | 5,901 | 5,830 | ||||||||
| ASU 2014-09 | |||||||||||
| Net sales | 126,956 | 106,646 | 102,982 | 112,795 | 119,965 | 99,586 | 105,257 | 93,323 | 449,379 | 418,131 | 382,090 |
| Cost of Sales | 422,303 | 390,800 | 355,517 | ||||||||
| Gross profit | 27,076 | 27,331 | 26,573 | ||||||||
| Income from operations | 7,813 | 8,616 | 8,510 | ||||||||
| Net Income | $ 5,062 | $ 5,901 | $ 5,830 | ||||||||
| Basic and diluted income per common share (in dollars per share) | $ 1.13 | $ 1.25 | $ 1.22 | ||||||||
| ASU 2014-09 | Hardware and software product | |||||||||||
| Net sales | $ 143,920 | $ 148,949 | $ 148,444 | ||||||||
| ASU 2014-09 | Software - security and highly interdependent with support | |||||||||||
| Net sales | 120,806 | 95,438 | 77,100 | ||||||||
| ASU 2014-09 | Maintenance, support and other services revenue | |||||||||||
| Net sales | 184,653 | 173,744 | 156,546 | ||||||||
| ASU 2014-09 | Expected Impact of Adoption | |||||||||||
| Net sales | (82,520) | (67,627) | (63,961) | (74,704) | (75,411) | (60,981) | (58,989) | (58,141) | (288,812) | (253,522) | (218,356) |
| Cost of Sales | (288,812) | (253,522) | (218,356) | ||||||||
| ASU 2014-09 | Expected Impact of Adoption | Hardware and software product | |||||||||||
| Net sales | 0 | ||||||||||
| ASU 2014-09 | Expected Impact of Adoption | Software - security and highly interdependent with support | |||||||||||
| Net sales | (114,867) | (90,522) | (73,192) | ||||||||
| ASU 2014-09 | Expected Impact of Adoption | Maintenance, support and other services revenue | |||||||||||
| Net sales | (173,945) | (163,000) | (145,164) | ||||||||
| ASU 2014-09 | As Adjusted | |||||||||||
| Net sales | $ 44,436 | $ 39,019 | $ 39,021 | $ 38,091 | $ 44,554 | $ 38,605 | $ 46,268 | $ 35,182 | 160,567 | 164,609 | 163,734 |
| Cost of Sales | 133,491 | 137,278 | 137,161 | ||||||||
| Gross profit | 27,076 | 27,331 | 26,573 | ||||||||
| Income from operations | 7,813 | 8,616 | 8,510 | ||||||||
| Net Income | $ 5,062 | $ 5,901 | $ 5,830 | ||||||||
| Basic and diluted income per common share (in dollars per share) | $ 1.13 | $ 1.25 | $ 1.22 | ||||||||
| ASU 2014-09 | As Adjusted | Hardware and software product | |||||||||||
| Net sales | $ 143,920 | $ 148,949 | $ 148,444 | ||||||||
| ASU 2014-09 | As Adjusted | Software - security and highly interdependent with support | |||||||||||
| Net sales | 5,939 | 4,916 | 3,908 | ||||||||
| ASU 2014-09 | As Adjusted | Maintenance, support and other services revenue | |||||||||||
| Net sales | $ 10,708 | $ 10,744 | $ 11,382 | ||||||||