Consolidated Statements of Operations $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Revenues	$ 1,693,481	$ 1,511,081	$ 1,378,053
Costs and expenses:
Operating	1,089,605	976,316	884,232
Selling	305,624	271,882	242,453
General and administrative	132,571	116,036	99,784
Depreciation	53,571	51,969	52,927
Amortization of intangible assets	5,072	3,228	3,044
Gain on sale of assets, net	(7,169)	(8,586)	(5,653)
Costs and expenses	1,579,274	1,410,845	1,276,787
Income from operations	114,207	100,236	101,266
Other income (expense):
Interest expense	(13,745)	(6,129)	(4,973)
Interest income	1,894	955	175
Other income (expense), net	(5,120)	(9,863)	(7,021)
Income before income taxes	97,236	85,199	89,447
Income taxes	25,096	23,909	23,748
Net income	$ 72,140	$ 61,290	$ 65,699
Earnings per share--basic
Earnings per share--basic | $ / shares	$ 1.66	$ 1.38	$ 1.46
Earnings per share--diluted | $ / shares	$ 1.58	$ 1.31	$ 1.38
Weighted-average shares outstanding:
Basic | shares	43,451,661	44,447,675	45,081,254
Diluted | shares	45,537,698	46,737,371	47,590,076
Stock split, conversion ratio	2