Risk of Market Price Discount From Net Asset Value [Member] Investment Risk [Member] Market Risks [Member] Infrastructure Companies Risk [Member] Common Stock Risk [Member] Concentration in Infrastructure Companies Risk [Member] Debt Securities Risk [Member] Below Investment Grade and Unrated Securities Risk [Member] Contingent Capital Securities Risk [Member] Foreign Non U S and Emerging Market Securities Risk [Member] Foreign Currency and Currency Hedging Risk [Member] Warrants and Rights Risk [Member] Options Risk [Member] Convertible Securities Risk [Member] MLPs and Energy Investments Risks [Member] Energy Sector Risks [Member] Utilities Sector Risks [Member] Interest Rate Risk to MLPs and Energy Investments [Member] Industry Specific Risks [Member] Special Purpose Acquisition Companies Risk [Member] Derivatives and Hedging Transactions RISK [Member] Regulatory Risk [Member] Other Investment Companies Risk [Member] Restricted and Illiquid Securities Risk [Member] Leverage Risk [Member] Inflation Risk [Member] Loans of Portfolio Securities [Member] Tax Risk [Member] Active Management Risk [Member] Potential Conflicts of Interest Risk [Member] Dependence on Key Personnel Risk [Member] Portfolio Turnover Risk [Member] Anti Takeover Provisions [Member] Market Disruption and Geopolitical Risk [Member] Changes in Trade Negotiations Risk [Member] Cyber Security Risk [Member] Risks of Securities Linked to the Real Estate Market [Member] Financial Sector and Financial Institutions Risk [Member] Insurance Company Investment Risk [Member] Special Risks to Holders of Common Shares [Member] Offering Expenses [Member] Common Shares [Member]