v3.8.0.1

Equity - Summary of Redemptions under Company's Share Redemption Program (Detail) shares in Thousands, $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($) Stockholder shares | Dec. 31, 2016 USD ($) Stockholder shares | Dec. 31, 2015 USD ($) Stockholder shares
Equity [Abstract] |  |  |
Number of stockholders | Stockholder | 32 | 27 | 15
Number of shares | shares | 119 | 109 | 43
Aggregate redemption price | $ | $ 9,439 | $ 8,154 | $ 3,054

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- Definition Number of stockholders. + References No definition available. + Details
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Period Type: | duration

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- References No definition available. + Details
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- Definition Number of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
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- Definition Equity impact of the value of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
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