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Compensation Plans - Expense Recognition of Deferred Compensation (Detail) - Restricted Stock Units (RSUs)	Jun. 30, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2018 (Remaining Period)	$ 3,699,502
2019	6,807,766
2020	5,333,844
2021	4,011,302
2022	3,024,169
Thereafter	1,143,286
Total	$ 24,019,869

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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