Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Date the declared dividend will be paid, in CCYY-MM-DD format.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Topic 210
-SubTopic 10
-Section 45
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6935-107765

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Stockholders' Equity - Dividend Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 28, 2011	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 07, 2018	Apr. 05, 2018	Dec. 07, 2017	Sep. 07, 2017	Jun. 08, 2017	Apr. 06, 2017
Dividends Payable [Line Items]
Per Share Amount		$ 0.070	$ 0.055	$ 0.140	$ 0.110
Installment FY 2018 [Member]
Dividends Payable [Line Items]
Record Date				Mar. 22, 2018
Payment Date				Apr. 05, 2018
Per Share Amount	$ 0.070
Dividend Payment							$ 1,351
Installment 1 FY 2018 [Member]
Dividends Payable [Line Items]
Record Date				May 22, 2018
Payment Date				Jun. 07, 2018
Per Share Amount	0.070
Dividend Payment						$ 1,353
Installment 1 FY 2017 [Member]
Dividends Payable [Line Items]
Record Date				Mar. 22, 2017
Payment Date				Apr. 06, 2017
Per Share Amount	0.055
Dividend Payment											$ 1,029
Installment 2 FY 2017 [Member]
Dividends Payable [Line Items]
Record Date				May 24, 2017
Payment Date				Jun. 08, 2017
Per Share Amount	0.055
Dividend Payment										$ 1,036
Installment 3 FY 2017 [Member]
Dividends Payable [Line Items]
Record Date				Aug. 23, 2017
Payment Date				Sep. 07, 2017
Per Share Amount	0.055
Dividend Payment									$ 1,055
Installment 4 FY 2017 [Member]
Dividends Payable [Line Items]
Record Date				Nov. 22, 2017
Payment Date				Dec. 07, 2017
Per Share Amount	$ 0.055
Dividend Payment								$ 1,060