Income Taxes [Line Items]

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: 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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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
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-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=84176650&loc=d3e32123-109318

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- Definition

The aggregate cash inflow comprised of the amount received from (a) employees to acquire the entity's shares under incentive awards, including stock option exercises and restricted stock arrangements, and (b) the excess tax benefit arising from such transactions.

+ References

No definition available.

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- Definition

Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28446-109314

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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Income tax expense (benefit)	$ 2,170		$ 3,584	$ 6,302	$ 9,110
Effective income tax rate				32.60%	43.40%
Tax expense due to valuation allowance on capital loss generated from investments							$ 600
Settlement of Options and Restricted Stock Units [Member]
Income Taxes [Line Items]
Tax benefit recognized				$ 300
Settlement from Tax Audit [Member]
Income Taxes [Line Items]
Tax benefit recognized		$ (1,300)
Anticipated [Member]
Income Taxes [Line Items]
Effective income tax rate						35.00%