CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$ 34,352	$ 55,435	$ 90,954
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	7,447	(8,222)	(2,462)
Derivative instruments	(924)	3,823	0
Pension and postretirement plans	(13)	(15)	(16)
Total other comprehensive income (loss), net of tax	6,510	(4,414)	(2,478)
Total comprehensive income	40,862	51,021	88,476
Comprehensive income (loss) attributable to noncontrolling interest, net of tax:
Net earnings	204	84	68
Foreign currency translation adjustments	14	(113)	15
Comprehensive income (loss) attributable to noncontrolling interest, net of tax	218	(29)	83
Comprehensive income attributable to SMP	$ 40,644	$ 51,050	$ 88,393