Fair Value Measurements - Additional Information (Detail) $ in Millions	12 Months Ended
Feb. 28, 2018 USD ($) Vendor
Fair Value Disclosures [Abstract]
Transfers out of level 3 \| $	$ 0
Number of primary vendors \| Vendor	1
Investments that are communicated to the third party for consideration of reasonableness, threshold limit for fair values	0.50%

Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration