Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Rental	$ 353,889	$ 318,774	$ 289,417
Rental related services	101,038	82,907	78,068
Rental operations	454,927	401,681	367,485
Revenues	115,303	96,649	94,549
Total revenues	570,230	498,330	462,034
Direct costs of rental operations:
Depreciation of rental equipment	80,391	73,139	69,908
Rental related services	76,241	64,298	60,029
Other	79,365	68,678	65,472
Total direct costs of rental operations	235,997	206,115	195,409
Costs of sales	68,068	58,964	60,280
Total costs of revenues	304,065	265,079	255,689
Gross profit	266,165	233,251	206,345
Selling and administrative expenses	124,793	115,770	111,605
Income from operations	141,372	117,481	94,740
Other income (expense):
Interest expense	(12,331)	(12,297)	(11,622)
Foreign currency exchange gain (loss)	84	(489)	334
Income before provision for income taxes	129,125	104,695	83,452
Provision (benefit) for income taxes	32,319	25,289	(70,468)
Net income	$ 96,806	$ 79,406	$ 153,920
Earnings per share:
Basic	$ 3.99	$ 3.29	$ 6.41
Diluted	$ 3.93	$ 3.24	$ 6.34
Shares used in per share calculation:
Basic	24,250	24,141	23,999
Diluted	24,623	24,540	24,269
Cash dividends declared per share	$ 1.50	$ 1.36	$ 1.04
Sales [Member]
Revenues
Revenues	$ 110,229	$ 92,618	$ 91,500
Other [Member]
Revenues
Revenues	$ 5,074	$ 4,031	$ 3,049