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Long-Term Debt - Additional Information (Detail) | 0 Months Ended |  | 9 Months Ended |  | 9 Months Ended |  | 9 Months Ended |  | 9 Months Ended |  | 9 Months Ended |  |
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Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 IKB Loan [Member] Installment DebtAgreements | Apr. 11, 2013 IKB Loan [Member] USD ($) | Apr. 11, 2013 IKB Loan [Member] EUR (€) | Sep. 30, 2014 2014 IKB Loan [Member] Installment | Sep. 04, 2014 2014 IKB Loan [Member] USD ($) | Sep. 04, 2014 2014 IKB Loan [Member] EUR (€) | Sep. 30, 2014 Maximum [Member] | Sep. 30, 2014 Federal Funds Rate [Member] | Sep. 30, 2014 5.375% Notes [Member] | Oct. 03, 2012 5.375% Notes [Member] USD ($) | Sep. 30, 2014 Revolving Credit Facility [Member] | Nov. 21, 2011 Revolving Credit Facility [Member] USD ($) | Sep. 30, 2014 Revolving Credit Facility, Due Nov. 2016 [Member] | Sep. 30, 2014 Revolving Credit Facility, Due Nov. 2016 [Member] Minimum [Member] | Sep. 30, 2014 Revolving Credit Facility, Due Nov. 2016 [Member] Maximum [Member] | Sep. 30, 2014 Revolving Credit Facility, Due Nov. 2016 [Member] Daily Euro Rate [Member] Minimum [Member] | Sep. 30, 2014 Revolving Credit Facility, Due Nov. 2016 [Member] Daily Euro Rate [Member] Maximum [Member] | Sep. 30, 2014 Letters of Credit [Member] USD ($) | Dec. 31, 2013 Letters of Credit [Member] USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 350,000,000 |  |  |  |  |  |  |
Debt instrument maturity date |  |  |  |  |  |  |  |  |  |  | Oct. 15, 2020 |  | Nov. 21, 2016 |  | Nov. 30, 2016 |  |  |  |  |  |
Federal fund rate spread |  |  |  |  |  |  |  |  |  | 0.50% |  |  |  |  |  | 0.25% | 1.25% | 1.25% | 2.25% |  |
Margin over Euro-rate |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio | 2.3 |  |  |  |  |  |  |  | 3.5 |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  | 57,600,000 | 42,700,000 |  | 12,600,000 | 10,000,000 |  |  |  | 250,000,000 |  |  |  |  |  |  |  |  |
Percentage of aggregate principal amount of outstanding |  |  | 2.05% |  |  | 2.40% |  |  |  |  | 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. |  |  |  |  |  |  |  |  |  |
Number of separate loan agreement |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of installments |  |  | 32 |  |  | 27 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Installments beginning date |  |  | Jun. 30, 2015 |  |  | Sep. 30, 2015 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Installments ending date |  |  | Mar. 31, 2023 |  |  | Jun. 30, 2022 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Letters of credit issued |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,200,000 | 5,200,000
Letters of credit outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 |

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