Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011		Dec. 31, 2010
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 488,000	$ 415,000		$ 570,000
Additions Charged to Costs and Expenses	115,000	126,000		345,000
Additions Charged to Other Accounts		76,000	[1]
Deductions	37,000	129,000		500,000
Balance at End of Period	566,000	488,000		415,000
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	2,008,000	1,323,000		700,000
Additions Charged to Costs and Expenses	2,182,000	685,000		623,000
Deductions	70,000
Balance at End of Period	$ 4,120,000	$ 2,008,000		$ 1,323,000

[1] Related to acquisitions.