Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 4,935	$ 13,451	$ 12,609	$ 4,137
Receivables, net	118,101	111,562
Inventories	13,444	15,671
Rental fleet, net	925,956	989,154
Property, plant and equipment, net	155,621	157,304
Other assets	17,586	15,334
Intangibles, net	57,164	62,024
Goodwill	706,768	708,907
Total assets	1,999,575	2,073,407
Liabilities:
Accounts payable	32,610	26,955
Accrued liabilities	80,114	78,084
Lines of credit	610,223	634,285
Obligations under capital leases	61,853	52,791
Senior notes, net	246,329	245,850
Deferred income taxes	158,758	173,754
Total liabilities	1,189,887	1,211,719
Commitments and contingencies
Stockholders' equity:
Common stock	500	497
Additional paid-in capital	616,850	605,369
Retained earnings	407,559	463,322
Accumulated other comprehensive loss	(67,387)	(60,334)
Treasury stock, at cost	(147,834)	(147,166)
Total stockholders' equity	809,688	861,688
Total liabilities and stockholders' equity	1,999,575	2,073,407
Eliminations
ASSETS
Intercompany receivables	(182,513)	(150,661)
Total assets	(182,513)	(150,661)
Liabilities:
Intercompany payables	(34,514)	(2,662)
Total liabilities	(34,514)	(2,662)
Commitments and contingencies
Stockholders' equity:
Additional paid-in capital	(147,999)	(147,999)
Total stockholders' equity	(147,999)	(147,999)
Total liabilities and stockholders' equity	(182,513)	(150,661)
Guarantors
ASSETS
Cash and cash equivalents	1,795	803	1,456	1,260
Receivables, net	100,273	91,624
Inventories	11,449	13,471
Rental fleet, net	773,823	823,997
Property, plant and equipment, net	131,802	133,919
Other assets	14,906	13,324
Intangibles, net	56,734	61,360
Goodwill	645,126	645,126
Intercompany receivables	148,005	145,855
Total assets	1,883,913	1,929,479
Liabilities:
Accounts payable	26,150	21,004
Accrued liabilities	71,431	71,298
Lines of credit	599,470	634,285
Obligations under capital leases	61,738	52,648
Senior notes, net	246,329	245,850
Deferred income taxes	139,931	153,345
Intercompany payables	29,583	1,437
Total liabilities	1,174,632	1,179,867
Commitments and contingencies
Stockholders' equity:
Common stock	500	497
Additional paid-in capital	616,850	605,369
Retained earnings	239,765	290,912
Treasury stock, at cost	(147,834)	(147,166)
Total stockholders' equity	709,281	749,612
Total liabilities and stockholders' equity	1,883,913	1,929,479
Non-Guarantors
ASSETS
Cash and cash equivalents	3,140	12,648	$ 11,153	$ 2,877
Receivables, net	17,828	19,938
Inventories	1,995	2,200
Rental fleet, net	152,133	165,157
Property, plant and equipment, net	23,819	23,385
Other assets	2,680	2,010
Intangibles, net	430	664
Goodwill	61,642	63,781
Intercompany receivables	34,508	4,806
Total assets	298,175	294,589
Liabilities:
Accounts payable	6,460	5,951
Accrued liabilities	8,683	6,786
Lines of credit	10,753
Obligations under capital leases	115	143
Deferred income taxes	18,827	20,409
Intercompany payables	4,931	1,225
Total liabilities	49,769	34,514
Commitments and contingencies
Stockholders' equity:
Additional paid-in capital	147,999	147,999
Retained earnings	167,794	172,410
Accumulated other comprehensive loss	(67,387)	(60,334)
Total stockholders' equity	248,406	260,075
Total liabilities and stockholders' equity	$ 298,175	$ 294,589