Term Preferred Shares [Member] Common Stock [Member] Mandatorily Redeemable Preferred Stock [Member] Notes Payable [Member] 6.75% UNSECURED NOTES DUE 2031 [Member] 6.75% Unsecured Notes due 2031 [Member] 5.00% Unsecured Notes due 2027 [Member] 8.75% Unsecured Notes Due 2030 [Member] 8.50% Series 2017 Term Preferred Shares [Member] 7.50% Series 2023 Term Preferred Shares [Member] 8.125% Series 2024 Term Preferred Shares [Member] 6.75% Series 2024 Term Preferred Shares [Member] 6.25% Series 2027 Term Preferred Shares [Member] 6.00% Series 2029 Term Preferred Shares [Member] 7.125% Series 2029 Term Preferred Shares [Member] Seven Point One Twenty Five Percentage Series Two Thousand Twenty Nine Term Preferred Shares [Member] Repurchase Agreement [Member] 8.75% Unsecured Notes due 2030 [Member] Risks Relating to Our Business and Structure [Member] Risks Related to U.S. Federal Tax Regulation [Member] Risks Relating to Our Investments [Member] Risks Relating to an Investment in Our Securities [Member] Risks Relating to Our Business and Structure one [Member] Six Percentage Series Two Thousand Twenty Nine Term Preferred Shares Member Mandatorily Redeemable Preferred Stock [Member] Eight Point Fifty Percentage Series Two Thousand And Seventeen Term Preferred Shares Member Six Point Seventy Five Unsecured Notes Due2031 Member Eight Point One Twenty Five Percentage Series Two Thousand Twenty Four Term Preferred Shares Member Six Point Seventy Five Percentage Series Two Thousand Twenty Four Term Preferred Shares Member Eight Point Seven Five Unsecured Notes Due Two Zero Three Zero Member Term Preferred Shares Member Six Point Twenty Five Percentage Series Two Thousand Twenty Seven Term Preferred Shares Member Five Percentage Unsecured Notes Due2027 Member Risks Relating To An Investment In Our Securities Member Risks Relating To Our Business And Structure Member sixsevenfive UNSECUREDNOTESDUE2031 Member Seven Point Fifty Percentage Series Two Thousand Twenty Three Term Preferred Shares Member Risks Relating To Our Investments Member Seven One Two Five Series Two Zero Twonine Term Preferred Shares Member Seven Point One Twenty Five Percentage Series Two Thousand Twenty Nine Term Preferred Shares Member Risks Related To USFederal Tax Regulation Member Notes Payable Member Risks Relating To Our Business And Structure One Member Common Stock [Member] Repurchase Agreement Member Eight Seven Five Unsecured Notes Due Two Zero Three Zero Member