Property, Plant and Equipment (Narrative) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Depreciation	$ 14,116,000	$ 11,451,000	$ 11,261,000
Depreciation expense for capitalized computer software costs	5,700,000	4,100,000	3,900,000
Unamortized computer software costs	$ 19,000,000	$ 13,800,000