Share-Based Compensation - Summary of RSUs and MRSUs (Detail)	3 Months Ended
Jun. 30, 2017 shares
Restricted Stock Units (RSUs) [Member] \| Time Based Vesting [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs or MRSUs Outstanding	293,841
Weighted Average Remaining Vesting Period (Months)	16 months
Restricted Stock Units (RSUs) [Member] \| Milestone Vesting [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs or MRSUs Outstanding	290,000
Multi Year Performance Based Restricted Stock Units [Member] \| Vesting Based on $60 Share Price [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs or MRSUs Outstanding	114,500
Period in which the target must be achieved, start date	Apr. 01, 2018
Period in which the target must be achieved, end date	Dec. 31, 2018
Multi Year Performance Based Restricted Stock Units [Member] \| Vesting Based on $40 Share Price [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs or MRSUs Outstanding	127,000
Period in which the target must be achieved, start date	Apr. 01, 2018
Period in which the target must be achieved, end date	Dec. 31, 2018
Multi Year Performance Based Restricted Stock Units [Member] \| Vesting Based on $22 Share Price [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs or MRSUs Outstanding	166,000
Period in which the target must be achieved, start date	Apr. 01, 2019
Period in which the target must be achieved, end date	Dec. 31, 2019

Share based compensation arrangement by share based payment Award, period in which target must be achieved, end date.

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- Definition

Share based compensation arrangement by share based payment award period in which target must be achieved, start date.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

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)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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