Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Rental	$ 351,790	$ 353,889	$ 318,774
Rental related services	92,393	101,038	82,907
Rental operations	444,183	454,927	401,681
Revenues	128,371	115,303	96,649
Total revenues	572,554	570,230	498,330
Direct costs of rental operations:
Depreciation of rental equipment	85,866	80,391	73,139
Rental related services	68,105	76,241	64,298
Other	73,818	79,365	68,678
Total direct costs of rental operations	227,789	235,997	206,115
Costs of sales	81,019	68,068	58,964
Total costs of revenues	308,808	304,065	265,079
Gross profit	263,746	266,165	233,251
Selling and administrative expenses	122,993	124,793	115,770
Income from operations	140,753	141,372	117,481
Other income (expense):
Interest expense	(8,787)	(12,331)	(12,297)
Foreign currency exchange gain	78	84	(489)
Income before provision for income taxes	132,044	129,125	104,695
Provision for income taxes	30,060	32,319	25,289
Net income	$ 101,984	$ 96,806	$ 79,406
Earnings per share:
Basic	$ 4.22	$ 3.99	$ 3.29
Diluted	$ 4.16	$ 3.93	$ 3.24
Shares used in per share calculation:
Basic	24,157	24,250	24,141
Diluted	24,531	24,623	24,540
Cash dividends declared per share	$ 1.68	$ 1.50	$ 1.36
Sales [Member]
Revenues
Revenues	$ 124,604	$ 110,229	$ 92,618
Other [Member]
Revenues
Revenues	$ 3,767	$ 5,074	$ 4,031