Related Parties - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Relative of Harry Kellogg, an executive officer	Jun. 30, 2011 Relative of Harry Kellogg, an executive officer	Dec. 31, 2011 Beneficial Owner Lower Limit
Related Party Transaction [Line Items]
Line of credit expiration date	2011-05
Revolving line of credit facility, outstanding amount	$ 0	$ 0		$ 0.7
Amount of principal outstanding			0.7
Proceed from repayment of principal of the loan			0.2
Financial receivable charges off			$ 0.5
Percentage of equity securities					10.00%