Common stock dividend rate percentage.

No definition available.

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

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

+ References

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

+ Details

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- Definition

Number of shares of common stock issued as dividends during the period. Excludes stock splits.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

+ Details

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- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount remaining of a stock repurchase plan authorized.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Details

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- Details

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Shareholders Equity - Additional Information (Detail) - USD ($)								3 Months Ended		9 Months Ended
	Sep. 13, 2019	Aug. 06, 2019	Jun. 21, 2019	May 24, 2019	Jun. 15, 2018	May 08, 2018	Mar. 07, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Feb. 20, 2018	May 03, 2016
Class of Stock [Line Items]
Dividend declared per common share (in dollars per share)		$ 0.31		$ 0.31		$ 0.27		$ 0.31	$ 0.27	$ 0.93	$ 0.81
Cash dividends paid - common shares, total	$ 10,900,000		$ 10,800,000		$ 9,400,000					$ 32,500,000	$ 28,000,000.0
Stock dividend percent									15.00%		15.00%
2016 Repurchase Authorization [Member]
Class of Stock [Line Items]
Total number of shares authorized for purchase													$ 150,000,000.0
Remaining number of shares available under repurchase authorization								$ 53,300,000		$ 53,300,000
Stock Dividend [Member]
Class of Stock [Line Items]
Stock dividend percent												15.00%
Additional stock issued as dividend (in shares)							4,397,520