Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net income attributable to Sterling common stockholders	$ 3,115	$ 1,815
Denominator:
Weighted average common shares outstanding - basic (in shares)	27,736	26,377
Shares for dilutive unvested stock and warrants (in shares)	256	346
Weighted average common shares outstanding - diluted (in shares)	27,992	26,723
Basic net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.11	$ 0.07
Diluted net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.11	$ 0.07