Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Name:	us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The Tax Cuts and Jobs Act (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
The Tax Cuts and Jobs Act (Details) - USD ($) $ in Millions	Dec. 22, 2017	Jan. 31, 2019	Jan. 31, 2018
The Tax Cuts and Jobs Act (Textual)
U.S. federal statutory corporate tax rate		26.90%
U.S. federal statutory tax rate, thereafter		21.00%
Federal net operating loss carryforwards		$ 11	$ 12
Minimum [Member]
The Tax Cuts and Jobs Act (Textual)
U.S. federal statutory corporate tax rate	21.00%
Maximum [Member]
The Tax Cuts and Jobs Act (Textual)
U.S. federal statutory corporate tax rate	35.00%