Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 50,466	$ 53,262	[1]
Short-term investments	53,797	51,740	[1]
Accounts receivable, net	36,253	41,922	[1]
Inventories:
Raw materials and purchased parts	46,868	47,186	[1]
Work in process	15,705	15,504	[1]
Finished goods	19,622	19,999	[1]
Total inventories	82,195	82,689	[1]
Deferred income taxes	6,351	6,646	[1]
Other current assets	8,310	7,557	[1]
Total current assets	237,372	243,816	[1]
Property, plant and equipment, at cost:
Land and land improvements	12,133	12,002	[1]
Buildings and building improvements	31,555	31,190	[1]
Machinery and equipment	39,051	38,007	[1]
Property plant and equipment, gross	82,739	81,199	[1]
Less accumulated depreciation and amortization	(45,556)	(44,218)	[1]
Net property, plant and equipment	37,183	36,981	[1]
Goodwill	59,066	58,060	[1]
Intangible assets, net	21,464	21,828	[1]
Other assets	940	923	[1]
Total assets	356,025	361,608	[1]
Current liabilities:
Accounts payable	16,421	18,625	[1]
Accrued compensation and benefits	10,332	12,652	[1]
Accrued warranty	6,727	6,801	[1]
Deferred profit	2,302	2,821	[1]
Income taxes payable	3,120	2,518	[1]
Other accrued liabilities	8,432	8,454	[1]
Total current liabilities	47,334	51,871	[1]
Other accrued liabilities	6,003	5,964	[1]
Deferred income taxes	12,441	12,742	[1]
Commitments and contingencies			[1]
Stockholders' equity:
Preferred stock, $1 par value; 1,000 shares authorized, none issued			[1]
Common stock, $1 par value; 60,000 shares authorized, 24,363 shares issued and outstanding in 2012 and shares 24,330 in 2011	24,363	24,330	[1]
Paid-in capital	78,899	77,658	[1]
Retained earnings	184,370	189,055	[1]
Accumulated other comprehensive income (loss)	2,615	(12)	[1]
Total stockholders' equity	290,247	291,031	[1]
Total liabilities and stockholders' equity	$ 356,025	$ 361,608	[1]

[1] Derived from December 31, 2011 audited financial statements.