Stock Option Plans and Share-Based Compensation - Stock Option Rollforward (Details) (Stock Options, USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2014
Stock Options
Options, Number of Shares:
Outstanding at beginning of period	3,143
Granted	397
Exercised	(786)
Forfeited	(72)
Expired	(12)
Outstanding at end of period	2,670
Vested and expected to vest	2,638
Exercisable	1,612
Options, Weighted-Average Exercise Price (in dollars per share):
Outstanding, beginning of period	$ 15.82
Granted	$ 26.14
Exercised	$ 14.44
Forfeited	$ 18.96
Expired	$ 19.88
Outstanding, end of period	$ 17.66
Vested and expected to vest	$ 17.60
Exercisable	$ 15.47

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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