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Income Taxes - Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations (Detail) | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Percent [Abstract] |  |  |
Statutory rate | 35.00% | 35.00% | 35.00%
Tax reform | 3.10% | 0.00% | 0.00%
State tax, net of federal benefit | 2.60% | 3.10% | 3.00%
Reverse federal impact of indemnification adjustments | 2.50% | (0.70%) | 0.10%
Unrecognized tax benefits, U.S. federal and state, net of federal benefit | (2.00%) | 1.60% | (0.50%)
Excess tax benefits/deficiencies for employee stock-based compensation, federal and state, net of federal benefit | (1.70%) | 0.00% | 0.00%
Impact of state rate change on net deferred tax liabilities, net of federal benefit | 0.60% | (0.50%) | 0.50%
State, valuation allowance adjustments on net operating losses | 0.20% | 1.00% | (0.20%)
Other, net | 0.90% | 0.10% | (0.40%)
Effective tax rate | 41.20% | 39.60% | 37.50%

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- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Effective Tax Rate Reconciliation, Percent + References No definition available. + Details
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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 + Details
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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 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 + Details
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