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

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

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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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.

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

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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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No definition available.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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Dividends (Details Textual) - USD ($) $ / shares in Units, $ in Thousands										1 Months Ended					3 Months Ended		9 Months Ended
	May 15, 2018	Jan. 05, 2018	Dec. 07, 2017	Oct. 13, 2017	Sep. 13, 2017	Jun. 09, 2017	May 03, 2017	Apr. 14, 2017	Mar. 03, 2017	Sep. 14, 2018	Aug. 14, 2018	Jun. 22, 2018	Mar. 30, 2018	Feb. 28, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Common Stock, Dividends, Per Share, Declared															$ 0.30	$ 0.30	$ 0.90	$ 0.90
Dividends Payable, Date to be Paid	Jun. 22, 2018		Jan. 05, 2018		Oct. 13, 2017		Jun. 09, 2017		Apr. 14, 2017		Sep. 14, 2018			Mar. 30, 2018
Dividends Payable, Date of Record		Dec. 18, 2017		Sep. 25, 2017		May 22, 2017		Mar. 28, 2017		Aug. 31, 2018		May 31, 2018	Mar. 12, 2018
Dividends		$ 6,500		$ 1,800				$ 1,800
Dividends Payable										$ 1,800			$ 1,800
Payments of Ordinary Dividends, Common Stock						$ 1,800						$ 1,800					$ 11,864	$ 3,541
Dividends Payable, Date Declared	May 15, 2018		Dec. 07, 2017		Sep. 13, 2017		May 03, 2017		Mar. 03, 2017		Aug. 14, 2018			Feb. 28, 2018
Common Class A [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.30		$ 0.30		$ 0.30		$ 0.30		$ 0.30		$ 0.30			$ 0.30
Common Class B [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.30		$ 0.80		$ 0.30		$ 0.30		$ 0.30		$ 0.30			$ 0.30