CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
CURRENT ASSETS:
Cash and cash equivalents	$ 19,999	$ 21,755
Accounts receivable, less allowances for discounts and expected credit losses of $6,660 and $6,170 in 2022 and 2021, respectively	225,303	180,604
Inventories	534,421	468,755
Unreturned customer inventories	22,221	22,268
Prepaid expenses and other current assets	17,471	17,823
Total current assets	819,415	711,205
Property, plant and equipment, net of accumulated depreciation of $232,112 and $227,788 for 2022 and 2021, respectively	102,984	102,786
Operating lease right-of-use assets	42,116	40,469
Goodwill	131,538	131,652
Other intangibles, net	104,344	106,234
Deferred income taxes	35,964	36,126
Investments in unconsolidated affiliates	45,518	44,087
Other assets	28,530	25,402
Total assets	1,310,409	1,197,961
CURRENT LIABILITIES:
Notes payable	245,450	125,298
Current portion of other debt	3,235	3,117
Accounts payable	139,392	137,167
Sundry payables and accrued expenses	45,875	57,182
Accrued customer returns	46,085	42,412
Accrued core liability	23,513	23,663
Accrued rebates	42,606	42,472
Payroll and commissions	31,972	45,058
Total current liabilities	578,128	476,369
Long-term debt	0	21
Noncurrent operating lease liabilities	32,281	31,206
Other accrued liabilities	25,178	25,040
Accrued asbestos liabilities	51,909	52,698
Total liabilities	687,496	585,334
Commitments and contingencies
Stockholders' equity:
Common stock - par value $2.00 per share: Authorized - 30,000,000 shares; issued 23,936,036 shares	47,872	47,872
Capital in excess of par value	107,606	105,377
Retained earnings	545,830	532,319
Accumulated other comprehensive income	(8,815)	(8,169)
Treasury stock - at cost (2,011,019 shares and 1,911,792 shares in 2022 and 2021, respectively)	(80,622)	(75,819)
Total SMP stockholders' equity	611,871	601,580
Noncontrolling interest	11,042	11,047
Total stockholders' equity	622,913	612,627
Total liabilities and stockholders' equity	$ 1,310,409	$ 1,197,961