Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 101,984,000	$ 96,806,000	$ 79,406,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	94,643,000	89,476,000	81,975,000
Impairment of rental assets	0	0	39,000
Provision for doubtful accounts	1,343,000	1,013,000	581,000
Share-based compensation	5,549,000	5,892,000	4,111,000
Gain on sale of used rental equipment	(19,329,000)	(21,309,000)	(19,559,000)
Foreign currency exchange (gain) loss	(78,000)	(84,000)	489,000
Amortization of debt issuance costs	11,000	11,000	20,000
Change in:
Accounts receivable	3,440,000	(7,323,000)	(15,725,000)
Prepaid expenses and other assets	3,807,000	(13,530,000)	(9,351,000)
Accounts payable and accrued liabilities	316,000	20,298,000	(1,612,000)
Deferred income	(8,989,000)	5,138,000	10,258,000
Deferred income taxes	(2,193,000)	11,606,000	12,035,000
Net cash provided by operating activities	180,504,000	187,994,000	142,667,000
Cash Flows from Investing Activities:
Purchases of rental equipment	(86,329,000)	(167,703,000)	(123,071,000)
Purchases of property, plant and equipment	(13,724,000)	(12,080,000)	(15,664,000)
Cash paid for acquisition of business assets		(7,808,000)	(7,543,000)
Proceeds from sales of used rental equipment	47,052,000	44,447,000	41,786,000
Net cash used in investing activities	(53,001,000)	(143,144,000)	(104,492,000)
Cash Flows from Financing Activities:
Net (repayment) borrowing under bank lines of credit	(70,689,000)	(5,144,000)	15,130,000
Principal payments on Series A senior notes			(20,000,000)
Repurchase of common stock	(13,617,000)
Taxes paid related to net share settlement of stock awards	(4,376,000)	(3,333,000)	(3,257,000)
Payment of dividends	(39,769,000)	(35,539,000)	(30,939,000)
Net cash used in financing activities	(128,451,000)	(44,016,000)	(39,066,000)
Effect of foreign currency exchange rate changes on cash	(156,000)		(102,000)
Net (decrease) increase in cash	(1,104,000)	834,000	(993,000)
Cash balance, beginning of period	2,342,000	1,508,000	2,501,000
Cash balance, end of period	1,238,000	2,342,000	1,508,000
Supplemental Disclosure of Cash Flow Information:
Interest paid, during the period	9,050,000	12,475,000	12,598,000
Net income taxes paid, during the period	34,903,000	17,528,000	18,157,000
Dividends accrued during the period, not yet paid	10,083,000	9,489,000	8,388,000
Rental equipment acquisitions, not yet paid	$ 4,373,000	$ 6,496,000	$ 9,695,000