CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$ 9,187	$ 19,211	$ 21,144	$ 38,649
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	1,166	(6,528)	3,986	(7,166)
Derivative instruments	1,831	105	454	105
Pension and postretirement plans	(4)	(4)	(7)	(9)
Total other comprehensive income, net of tax	2,993	(6,427)	4,433	(7,070)
Total Comprehensive income	12,180	12,784	25,577	31,579
Comprehensive income (loss) attributable to noncontrolling interest, net of tax:
Net earnings	50	85	89	77
Foreign currency translation adjustments	(81)	(64)	(110)	(61)
Comprehensive income (loss) attributable to noncontrolling interest, net of tax	(31)	21	(21)	16
Comprehensive income attributable to SMP	$ 12,211	$ 12,763	$ 25,598	$ 31,563