Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income attributable to Sterling common stockholders	$ 18,210	$ 7,828	$ 21,325	$ 9,643
Denominator:
Weighted average common shares outstanding - basic (in shares)	27,941	26,338	27,794	26,357
Shares for dilutive unvested stock and warrants (in shares)	16	285	93	300
Weighted average common shares outstanding - diluted (in shares)	27,957	26,623	27,887	26,657
Basic net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.65	$ 0.30	$ 0.77	$ 0.37
Diluted net income per share attributable to Sterling common stockholders (in dollars per share)	$ 0.65	$ 0.29	$ 0.76	$ 0.36