Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward		$ 0	$ 0
Capital loss carryforwards		$ 0	$ 0
Federal statutory tax rate		35.00%
Income Tax benefit, new tax reform		$ (11,500,000)
Percentage of carryforward NOL limitation, new tax reform		80.00%
Tax Cuts And Jobs Act of 2017 \| Scenario, Plan
Schedule Of Income Taxes [Line Items]
Federal statutory tax rate	21.00%

Capital Loss Carryforwards

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- Definition

Schedule Of Income Taxes [Line Items]

+ References

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- Definition

Tax Cuts and Jobs Act of 2017, incomplete accounting, provisional income tax expense (benefit).

+ References

No definition available.

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- Definition

The percentage of taxable income eligible for the net operating loss deduction under the Tax Cuts and Jobs Act of 2017.

+ References

No definition available.

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- Definition

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

+ References

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

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-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

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-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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- Definition

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

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