3.24.3 html 104 55 1 true 52 0 false 4 false false R1.htm 995470 - Disclosure - N-2 Sheet http://xbrl.sec.gov/cef/role/N2 N-2 Cover 1 false false All Reports Book All Reports ck0001195738-20240831.xsd ck0001195738-20240831_def.xml ck0001195738-20240831_lab.xml ck0001195738-20240831_pre.xml d877975dncsr.htm g877975g1dsp001a.jpg g877975g1dsp01.jpg g877975g1g16g01.jpg g877975g1g16g02.jpg g877975g1g18g01.jpg g877975g1g18g02.jpg g877975g1g20g01.jpg g877975g1g20g02.jpg g877975g1g22g01.jpg g877975g1g22g02.jpg g877975g1g24g01.jpg g877975g1g24g02.jpg g877975g1g26g01.jpg g877975g1g26g02.jpg g877975g1g28g01.jpg g877975g1g28g02.jpg g877975g1g30g01.jpg g877975g1g30g02.jpg g877975g1g32g01.jpg g877975g1g32g02.jpg http://fasb.org/us-gaap/2024 http://xbrl.sec.gov/cef/2024 http://xbrl.sec.gov/dei/2024 true false