Interest Rate Risk [Member] Municipal Bond Risk [Member] Management Risk [Member] Market Risk [Member] Valuation Risk [Member] Leverage Risk [Member] Non-Diversification Risk [Member] Liquidity Risk [Member] Repurchase Offer Risks [Member] Market Risk Member Municipal Bond Risk Member Leverage Risk Member Non Diversification Risk Member Management Risk Member Repurchase Offer Risks Member Valuation Risk Member Interest Rate Risks Member Liquidity Risk Member