Supplemental Cash Flow Information - Details of Supplemental Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash paid during the period for:
Income taxes, net	$ 52,565us-gaap_IncomeTaxesPaidNet	$ 14,789us-gaap_IncomeTaxesPaidNet	$ 14,456us-gaap_IncomeTaxesPaidNet
Interest, net	1,048us-gaap_InterestPaidNet	800us-gaap_InterestPaidNet	554us-gaap_InterestPaidNet
Non-Cash Transaction Information:
Tax benefit from disqualifying dispositions of stock options and restricted stock	128	15	36
Shares tendered in payment of exercise price of stock options and SARs	84us-gaap_StockIssued1	0us-gaap_StockIssued1	161us-gaap_StockIssued1
Employee stock purchase plan	699	613	647
Equipment acquired under capital leases	313us-gaap_CapitalLeaseObligationsIncurred	1,929us-gaap_CapitalLeaseObligationsIncurred	672us-gaap_CapitalLeaseObligationsIncurred
Unsettled repurchases of common stock	1,425	0	2,498
Contingent consideration for acquisition	$ 477	$ 0	$ 0

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Future cash outflow to pay for repurchases of common stock that have occurred.

+ References

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Tax benefit from disqualifying dispositions of stock options and restricted stock.

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No definition available.

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Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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-Publisher FASB

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The increase during the period in capital lease obligations due to entering into new capital leases.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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The amount of cash paid for interest during the period net of cash paid for interest that is capitalized.

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The fair value of stock issued in noncash financing activities.

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Aggregate change in value for stock issued during the period as a result of employee stock purchase plan.

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