Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid in Capital	Treasury Stock	Retained Deficit	Accumulated Other Comprehensive Loss	Total Sterling Stockholders’ Equity	Non-controlling Interests
Beginning balance at Dec. 31, 2018	$ 172,260	$ 271	$ 233,795	$ (4,731)	$ (64,934)	$ 0	$ 164,401	$ 7,859
Beginning balance (in shares) at Dec. 31, 2018		26,597		467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,861				1,815		1,815	46
Loss on interest rate swap, net of tax	0
Stock-based compensation (in shares)		(1)
Stock-based compensation	1,021		1,021				1,021
Distributions to owners	(5,100)							(5,100)
Purchase of treasury stock (in shares)		250		250
Purchase of treasury stock	(3,201)			$ (3,201)			(3,201)
Issuance of stock (in shares)		130		(130)
Issuance of stock	0		(1,314)	$ 1,314			0
Shares withheld for taxes (in shares)		52		45
Shares withheld for taxes	(564)			$ (564)			(564)
Ending balance at Mar. 31, 2019	166,277	$ 271	233,502	$ (7,182)	(63,119)	0	163,472	2,805
Ending balance (in shares) at Mar. 31, 2019		26,424		632
Beginning balance at Dec. 31, 2019	221,211	$ 283	251,019	$ (6,142)	(25,033)	(209)	219,918	1,293
Beginning balance (in shares) at Dec. 31, 2019		27,772		518
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,215				3,115		3,115	100
Loss on interest rate swap, net of tax	$ (7,061)					(7,061)	(7,061)
Stock-based compensation (in shares)	138	0
Stock-based compensation	$ 2,234		2,234				2,234
Distributions to owners	0
Issuance of stock (in shares)		248		(248)
Issuance of stock	$ 103		(2,460)	$ 2,563			103
Shares withheld for taxes (in shares)	46	54		46
Shares withheld for taxes	$ (772)		(104)	$ (668)			(772)
Ending balance at Mar. 31, 2020	$ 218,930	$ 283	$ 250,689	$ (4,247)	$ (21,918)	$ (7,270)	$ 217,537	$ 1,393
Ending balance (in shares) at Mar. 31, 2020		27,966		316