Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Rental	$ 77,267	$ 69,953	$ 151,528	$ 137,931
Rental related services	19,086	18,796	36,917	36,731
Rental operations	96,353	88,749	188,445	174,662
Revenues			33,623	29,757
Total revenues	116,983	109,582	222,068	204,419
Direct costs of rental operations:
Depreciation of rental equipment	18,103	17,242	35,880	34,621
Rental related services	15,018	14,312	28,786	28,145
Other	18,753	16,039	35,022	31,398
Total direct costs of rental operations	51,874	47,593	99,688	94,164
Costs of sales	11,181	12,778	18,282	17,374
Total costs of revenues	63,055	60,371	117,970	111,538
Gross profit	53,928	49,211	104,098	92,881
Selling and administrative expenses	29,479	27,365	57,607	55,213
Income from operations	24,449	21,846	46,491	37,668
Other income (expense):
Interest expense	(2,999)	(2,949)	(5,991)	(5,738)
Foreign currency exchange gain (loss)	(344)	11	(376)	237
Income before provision for income taxes	21,106	18,908	40,124	32,167
Provision for income taxes	5,194	7,447	9,746	12,733
Net income	$ 15,912	$ 11,461	$ 30,378	$ 19,434
Earnings per share:
Basic	$ 0.66	$ 0.48	$ 1.26	$ 0.81
Diluted	$ 0.65	$ 0.48	$ 1.24	$ 0.80
Shares used in per share calculation:
Basic	24,145	23,985	24,106	23,968
Diluted	24,584	24,092	24,549	24,164
Cash dividends declared per share	$ 0.340	$ 0.260	$ 0.680	$ 0.520
Sales [Member]
Revenues
Revenues	$ 19,546	$ 20,187	$ 31,637	$ 28,482
Other [Member]
Revenues
Revenues	$ 1,084	$ 646	$ 1,986	$ 1,275