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Long-Term Debt - Additional Information (Detail)		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2015 USD ($) Installment DebtAgreements	Mar. 12, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 04, 2014 EUR (€)	Sep. 04, 2014 USD ($)	Apr. 11, 2013 EUR (€)	Apr. 11, 2013 USD ($)	Oct. 03, 2012 USD ($)
Debt Instrument [Line Items]
Margin over Euro-rate	1.00%	1.00%
Leverage ratio	210.00%
Other Assets [Member]
Debt Instrument [Line Items]
Aggregated unamortized deferred debt issuance costs	$ 5,800,000	$ 5,800,000
Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio		350.00%
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Federal fund rate spread		0.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 400,000,000
Debt instrument maturity date		Mar. 12, 2020
Revolving Credit Facility, Due Nov. 2016 [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Nov. 30, 2016
Revolving Credit Facility, Due Nov. 2016 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Federal fund rate spread		0.125%
Revolving Credit Facility, Due Nov. 2016 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Federal fund rate spread		1.00%
Revolving Credit Facility, Due Nov. 2016 [Member] | Daily Euro Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Federal fund rate spread		1.125%
Revolving Credit Facility, Due Nov. 2016 [Member] | Daily Euro Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Federal fund rate spread		2.00%
Letters of Credit [Member]
Debt Instrument [Line Items]
Letters of credit issued	5,300,000	$ 5,300,000		$ 5,300,000
Letters of credit outstanding	$ 0	$ 0
5.375% Notes [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Oct. 15, 2020
Aggregate principal amount									$ 250,000,000
Percentage of aggregate principal amount of outstanding	5.375%	5.375%							5.375%
Frequency of interest payable		Semiannually
Debt instrument redemption		The 5.375% Notes are redeemable, in whole or in part, at anytime on or after October 15, 2016 at the redemption prices specified in the applicable Indenture. Prior to October 15, 2016, we may redeem some or all of the Notes at a "make-whole" premium as specified in the Indenture.
IKB Loan [Member]
Debt Instrument [Line Items]
Aggregate principal amount							€ 42,700,000	$ 57,600,000
Percentage of aggregate principal amount of outstanding	2.05%	2.05%
Number of separate loan agreement | DebtAgreements		2
Number of installments | Installment		32
Installments beginning date		Jun. 30, 2015
Installments ending date		Mar. 31, 2023
2014 IKB Loan [Member]
Debt Instrument [Line Items]
Aggregate principal amount					€ 10,000,000	$ 12,600,000
Percentage of aggregate principal amount of outstanding	2.40%	2.40%
Frequency of interest payable		Quarterly
Number of installments | Installment		27
Installments beginning date		Sep. 30, 2015
Installments ending date		Jun. 30, 2022

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