1001 - Disclosure - N-2 - [Fee Table] link:presentationLink link:definitionLink link:calculationLink 1002 - Disclosure - N-2 - [Senior Securities] link:presentationLink link:definitionLink link:calculationLink 1003 - Disclosure - N-2 - [Investment Objectives] link:presentationLink link:definitionLink link:calculationLink 1004 - Disclosure - N-2 - [Risk Factors] link:presentationLink link:definitionLink link:calculationLink 1005 - Disclosure - N-2 - [Effects of Leverage] link:presentationLink link:definitionLink link:calculationLink 1006 - Disclosure - N-2 - [Share Price Table] link:presentationLink link:definitionLink link:calculationLink 1007 - Disclosure - N-2 - [Outstanding Securities] link:presentationLink link:definitionLink link:calculationLink Anti-Takeover Provisions [Member] Below Investment Grade Risk [Member] Build America Bonds B A Bs Risk [Member] Build America Bonds ("BABs") Risk [Member] Call Risk [Member] Counterparty Risk [Member] Credit Risk [Member] Credit Spread Risk [Member] Cybersecurity Risk [Member] Defaulted or Distressed Securities Risk [Member] Deflation Risk [Member] Derivatives Risk [Member] Direct Lending Risk [Member] Duration Risk [Member] Economic And Political Events Risk [Member] Economic Sector Risk [Member] Financial Futures And Options Transactions Risk [Member] Floating and Variable Rate Securities Risk [Member] Fund Tax Risk [Member] Global Economic Risk [Member] Hedging Risk [Member] Income Risk [Member] Inflation Risk [Member] Insurance Risk [Member] Inverse Floating Rate Securities Risk [Member] Investment And Market Risk [Member] Legislation And Regulatory Risk [Member] Leverage Risk [Member] Market Discount From Net Asset Value [Member] Municipal Securities Market Liquidity Risk [Member] Municipal Securities Market Risk [Member] Municipal Securities Risk [Member] Other Investment Companies Risk [Member] Recent Market Conditions [Member] Reinvestment Risk [Member] Restricted and Illiquid Investments Risk [Member] Reverse Repurchase Agreement Risk [Member] Special Risks Related To Certain Municipal Obligations [Member] Structured Products Risk [Member] Swap Transactions Risk [Member] Tobacco Settlement Bond Risk [Member] Unrated Securities Risk [Member] Valuation Risk [Member] When-Issued and Delayed-Delivery Transactions Risk [Member] Zero Coupon Bonds Risk [Member] At The Market Transaction [Member] Common Shares [Member] Interest And Other Related Expenses [Member]