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Earnings per Share - Common Stock Equivalents Not Included in Computation of Diluted Earnings Per Share (Detail) - $ / shares | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Restricted Stock [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share (in shares) | 37,298 | 13,750
Restricted Stock Units [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive securities excluded from computation of earnings per share (in shares) | 43,067 | 24,375
Minimum [Member] | Restricted Stock [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount | $ 9.84 | $ 13.96
Minimum [Member] | Restricted Stock Units [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount | 13.25 | 15.09
Maximum [Member] | Restricted Stock [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount | 14.49 | 13.96
Maximum [Member] | Restricted Stock Units [Member] |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount | $ 15.83 | $ 15.09

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic net Income or Loss per outstanding limited partnership unit in the future and that were not included in the computation of diluted net income per limited partnership unit, because to do so would increase net income per unit amounts or decrease loss per unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1533-109256 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1536-109256 + Details
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