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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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 2: http://www.xbrl.org/2003/role/presentationRef
-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 3: http://www.xbrl.org/2003/role/presentationRef
-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

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Data Type:	num:percentItemType
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Period Type:	duration

Income Taxes (Tax Cuts and Jobs Act of 2017) (Details) - USD ($) $ in Millions			12 Months Ended
	Dec. 22, 2017	Dec. 21, 2017	Dec. 31, 2018	Dec. 31, 2017
Tax Cuts and Jobs of Act 2017 [Line Items]
U.S. statutory rate (as a percent)	21.00%	35.00%		35.00%
Unites States
Tax Cuts and Jobs of Act 2017 [Line Items]
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense				$ 43.1
Forecast
Tax Cuts and Jobs of Act 2017 [Line Items]
Percentage of utilization of net operating losses			80.00%