QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($)
3 Months Ended 12 Months Ended
Dec. 30, 2016
Sep. 30, 2016
Jul. 01, 2016
Apr. 01, 2016
Jan. 01, 2016
Oct. 02, 2015
Jul. 03, 2015
Apr. 03, 2015
Dec. 30, 2016
Jan. 01, 2016
Jan. 02, 2015
QUARTERLY FINANCIAL INFORMATION (UNAUDITED)                      
Contract revenue $ 57,425,000 $ 58,660,000 $ 58,941,000 $ 33,915,000 $ 31,522,000 $ 33,511,000 $ 36,773,000 $ 33,297,000 $ 208,941,000 $ 135,103,000 $ 108,080,000
Income from operations 2,689,000 3,053,000 3,964,000 1,838,000 456,000 1,641,000 2,804,000 2,629,000 11,544,000 7,530,000 8,309,000
Income tax expense (benefit) 1,078,000 548,000 731,000 711,000 210,000 626,000 1,108,000 1,138,000 3,068,000 3,082,000 (990,000)
Net income $ 1,569,000 $ 2,462,000 $ 3,190,000 $ 1,078,000 $ 380,000 $ 782,000 $ 1,602,000 $ 1,495,000 $ 8,299,000 $ 4,259,000 $ 9,416,000
Earnings per share:                      
Basic (in dollars per share) $ 0.19 $ 0.30 $ 0.39 $ 0.13 $ 0.05 $ 0.10 $ 0.20 $ 0.19 $ 1.01 $ 0.54 $ 1.26
Diluted (in dollars per share) $ 0.18 $ 0.28 $ 0.37 $ 0.13 $ 0.05 $ 0.10 $ 0.20 $ 0.18 $ 0.97 $ 0.52 $ 1.22
Weighted-average shares outstanding:                      
Basic (in shares) 8,334,000 8,308,000 8,207,000 7,996,000 7,888,000 7,862,000 7,824,000 7,765,000 8,219,000 7,834,000 7,488,000
Diluted (in shares) 8,959,000 8,720,000 8,530,000 8,244,000 8,132,000 8,102,000 8,136,000 8,103,000 8,565,000 8,113,000 7,739,000