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

Income Taxes - Additional Information (Details)	9 Months Ended	12 Months Ended
Income Taxes - Additional Information (Details)	Sep. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Federal statutory tax rate		35.00%
Internal Revenue Service (IRS) \| Tax Year 2013
Income Tax Disclosure [Line Items]
Income tax examination year, audit by IRS completed	2013
Internal Revenue Service (IRS) \| Tax Year 2014
Income Tax Disclosure [Line Items]
Income tax examination year, audit by IRS completed	2014
Internal Revenue Service (IRS) \| Tax Year 2015
Income Tax Disclosure [Line Items]
Income tax examination year, audit by IRS completed	2015
Scenario Plan
Income Tax Disclosure [Line Items]
Federal statutory tax rate	21.00%