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Dividends and Distribution Payable - Federal Income Tax (Details) - $ / shares
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dividends Payable [Line Items]      
Dividends Payable, Amount Per Share $ 2.280 $ 2.155 $ 2.025
Dividend Declared, Ordinary Income [Member]      
Dividends Payable [Line Items]      
Dividends Payable, Amount Per Share 1.933 1.638 1.695
Dividend Declared, Return of Capital [Member]      
Dividends Payable [Line Items]      
Dividends Payable, Amount Per Share $ 0.347 $ 0.517 $ 0.330