Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Summary of Significant Accounting Policies - Debt (Details) - Senior Notes [Member] - USD ($)	Feb. 29, 2020	Feb. 28, 2019	Jan. 21, 2011
Unsecured Senior Notes Due March 31, 2018 [Member]
Debt Instrument [Line Items]
Fair value of notes	$ 125,300,000	$ 127,400,000
Unsecured Senior Notes Due January 2021 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 125,000,000.0