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Changes in Carrying Values of Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Goodwill [Line Items]
Beginning balance	$ 166,138
Effect of exchange rate changes	4,593
Ending balance	170,731
North America
Goodwill [Line Items]
Beginning balance	137,543
Effect of exchange rate changes	3,195
Ending balance	140,738
United Kingdom Segment
Goodwill [Line Items]
Beginning balance	1,145
Effect of exchange rate changes	98
Ending balance	1,243
Continental Europe
Goodwill [Line Items]
Beginning balance	6,884
Effect of exchange rate changes	831
Ending balance	7,715
Other
Goodwill [Line Items]
Beginning balance	20,566
Effect of exchange rate changes	469
Ending balance	$ 21,035

X

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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