Restructuring Impairments and Other Costs - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 12,000,000	$ 17,800,000
Selling, general and administrative expenses	1,144,890,000	1,148,731,000	936,847,000
Restructuring Reserve, Accrual Adjustment	2,337,000
Settlements of legal matters and an impairment of an intangible asset	1,400,000
Settlements of legal matters and impairment of long-term assets		7,900,000
Restructuring Orthodontic Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs			1,700,000
Selling, general and administrative expenses			3,300,000
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			1,900,000
Restructuring Reserve, Accrual Adjustment	8,000
Restructuring Prior Year Plans - 2010 and 2009
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment	2,300,000	800,000	500,000
Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 2,400,000	$ 5,200,000