Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Basis of Presentation [Abstract]
Percentage ownership of subsidiary (in hundredths)	97.00%
Cash and Cash Equivalents [Abstract]
Maximum time period for liquid investments to be considered cash equivalents (in months)	3M
Useful Lives [Abstract]
Estimated useful lives of intangible assets, minimum (in years)	3
Estimated useful lives of intangible assets, maximum (in years)	15
Foreign Currency Translation [Abstract]
Foreign currency transaction gains and (losses), net	$ (346,000)	$ (450,000)	$ 361,000
Allowance for doubtful accounts [Roll Forward]
Reserve balance, beginning of year	1,820,000	2,215,000	1,496,000
Provision	1,510,000	(11,000)	1,023,000
Write offs	(884,000)	(437,000)	(393,000)
Foreign exchange gain (loss)	(48,000)	53,000	89,000
Reserve balance, end of year	2,398,000	1,820,000	2,215,000
Advertising Costs [Abstract]
Advertising costs	3,583,000	3,056,000	3,002,000
Product Warranty Reserve [Abstract]
Product warranty reserve term, minimum (in months)	3
Standard product warranty term, maximum (in years)	1
Stock-Based Compensation [Abstract]
Number of types of stock-based compensation plans	2
Number of years RSU's can be earned based upon cumulative performance (in years)	5Y
Numerator Abstract]
Net income attributable to controlling interest	39,918,000	32,430,000	3,068,000
Denominator [Abstract]
Denominator for basic earnings per share (in shares)	22,588,721	22,517,246	22,446,940
Effect of dilutive securities [Abstract]
Employee stock options and restricted stock units (in shares)	294,234	214,668	172,525
Supplemental executive retirement plan (in shares)	101,266	97,885	96,315
Denominator for diluted earnings per share (in shares)	22,984,221	22,829,799	22,715,780
Net income attributable to controlling interest per share [Abstract]
Basic (in dollars per share)	$ 1.77	$ 1.44	$ 0.14
Diluted (in dollars per share)	$ 1.74	$ 1.42	$ 0.14
Earnings per Share [Abstract]
Antidilutive shares (in shares)	885	1,000	32,000
General Liability Insurance [Member]
Self-Insurance Reserves [Abstract]
Amount captive is liable per occurrence of claims	1,000,000
Amount captive is liable per year in the aggregate	2,500,000
Workers' Compensation Insurance [Member]
Self-Insurance Reserves [Abstract]
Amount captive is liable per occurrence of claims	350,000
Amount captive is liable per year in the aggregate	$ 3,250,000
Aviation Equipment [Member]
Useful Lives [Abstract]
Estimated useful lives of assets, average (in years)	20
Buildings [Member]
Useful Lives [Abstract]
Estimated useful lives of assets, average (in years)	40
Equipment [Member]
Useful Lives [Abstract]
Estimated useful lives of the assets, minimum (in years)	3
Estimated useful lives of the assets, maximum (in years)	10