Earnings per Share - Additional Information (Detail) - USD ($)	12 Months Ended
Feb. 28, 2018	Feb. 28, 2017	Feb. 29, 2016
Earnings Per Share [Abstract]
Undistributed earnings	$ 0
Stock options not included in the diluted earnings per share computation		42,500	145,243

The earnings that is allocated to common stock and participating securities to the extent that each security may share in earnings as if all of the earnings for the period had been distributed.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 65
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e2793-109256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60A
-URI http://asc.fasb.org/extlink&oid=96947427&loc=SL5780132-109256

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 66
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e2814-109256

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e2740-109256

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-URI http://asc.fasb.org/extlink&oid=96947427&loc=SL5780133-109256

Name:	us-gaap_UndistributedEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration