Consolidated Balance Sheets (UNAUDITED) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets
Allowance for doubtful accounts (owned fleet)	$ 658	$ 819
Accumulated depreciation on rental equipment	124,666	109,336
Accumulated depreciation on furniture, fixtures and equipment	1,072	1,006
Accumulated amortization on intangible assets	$ 6,940	$ 6,519
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	84,000,000	84,000,000
Common stock, shares issued (in shares)	19,295,359	19,295,359
Common stock, shares outstanding (in shares)	19,295,359	19,295,359