Note 16 - Segments - Segment Reporting Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues from external customers	$ 7,101,668	$ 5,126,142	$ 4,735,940
Interest income	639	657	713
Interest expense	19,763	2,427	9,727
Depreciation and amortization	55,665	53,354	57,456
Segment operating income	506,113	309,036	154,605
Segment income from continuing operations before taxes	509,327	313,683	151,723
Segment assets	3,821,066	3,119,977	2,985,393
Goodwill	416,363	370,331	292,142
Expenditures for segment assets	243,060	167,177	136,200
Truck Segment [Member]
Revenues from external customers	7,084,847	5,109,070	4,721,058
Interest income	639	657	713
Interest expense	19,763	2,119	9,444
Depreciation and amortization	55,354	53,096	57,162
Segment operating income	505,415	307,394	153,841
Segment income from continuing operations before taxes	508,629	312,350	151,222
Segment assets	3,769,007	3,068,365	2,939,390
Goodwill	413,803	367,771	289,582
Expenditures for segment assets	242,503	163,624	135,956
Other Segments [Member]
Revenues from external customers	16,821	17,072	14,882
Interest expense	0	308	283
Depreciation and amortization	311	258	294
Segment operating income	698	1,642	764
Segment income from continuing operations before taxes	698	1,333	501
Segment assets	52,059	51,612	46,003
Goodwill	2,560	2,560	2,560
Expenditures for segment assets	$ 557	$ 3,553	$ 244