Property, Plant and Equipment (Detail) - Property, Plant and Equipment (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Property, plant and equipment, at cost	$ 43,977,000	$ 44,457,000
Less accumulated depreciation	24,107,000	26,867,000
Property, plant and equipment, net	19,870,000	17,590,000
Land and Building [Member]
Property, Plant and Equipment, Useful Life	20 to 50
Property, plant and equipment, at cost	13,896,000	13,896,000
Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	5 to 12
Property, plant and equipment, at cost	28,406,000	27,277,000
Office Furniture and Equipment [Member]
Property, Plant and Equipment, Useful Life	3 to 10
Property, plant and equipment, at cost	1,153,000	1,168,000
Construction in Progress [Member]
Property, plant and equipment, at cost	$ 522,000	$ 2,116,000