Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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+ Details

- Definition

Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

+ References

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+ Details

Goodwill and Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended				3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Nov. 30, 2012	Dec. 31, 2012 Scanners and CAD/CAM Services	Sep. 30, 2012 Scanners and CAD/CAM Services	Dec. 31, 2012 Scanners and CAD/CAM Services	Dec. 31, 2012 Scanners and CAD/CAM Services	Dec. 31, 2011 Scanners and CAD/CAM Services	Dec. 31, 2010 Scanners and CAD/CAM Services
Goodwill [Line Items]
Impairment of goodwill	$ 36,591	$ 0	$ 0		$ 11,900	$ 24,700	$ 36,591	$ 36,591
Goodwill	$ 99,236	$ 135,383	$ 478		$ 40,693		$ 40,693	$ 40,693	$ 76,938	$ 0
Excess of goodwill over carrying value of net assets				10.00%
Discount Rate, Decrease Resulting in Impairment	1.90%
Customer Support Costs Increase Resulting in Impairment	(12.00%)
Terminal Growth Rate, Decrease Resulting in Impairment	1.00%