CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating revenue:
Equipment	$ 10,740	$ 9,035	$ 26,039	$ 17,230
Services	33,117	31,073	64,762	61,500
Total operating revenue	43,857	40,108	90,801	78,730
Costs and expenses:
Cost of sales, excluding depreciation and amortization	9,292	7,924	22,758	14,923
Cost of services, excluding depreciation and amortization	15,905	14,771	31,231	29,506
Selling, general and administrative expenses	7,441	6,729	14,147	13,272
Depreciation and amortization	6,732	5,682	12,926	11,361
Total costs and expenses	39,370	35,106	81,062	69,062
Operating income	4,487	5,002	9,739	9,668
Other income and expense:
Interest and other income	14	14	34	24
Interest expense	(1,482)	(1,015)	(2,846)	(2,083)
Total other (expense)	(1,468)	(1,001)	(2,812)	(2,059)
Income before income taxes	3,019	4,001	6,927	7,609
Income tax provision	1,210	1,307	2,796	2,773
Net income	$ 1,809	$ 2,694	$ 4,131	$ 4,836
Basic earnings per share	$ 0.13	$ 0.20	$ 0.31	$ 0.36
Weighted average common shares outstanding (in shares)	13,487,553	13,367,083	13,469,303	13,348,447
Diluted earnings per share	$ 0.13	$ 0.20	$ 0.31	$ 0.36
Weighted average common and equivalent shares outstanding (in shares)	13,500,046	13,380,186	13,483,967	13,360,949
Dividends per share (in dollars per share)	$ 0.14	$ 0.135	$ 0.28	$ 0.27