v3.25.2
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 60 Months Ended 110 Months Ended 120 Months Ended
May 31, 2025
May 31, 2025
May 31, 2025
May 31, 2025
Without Sales Load [Member] | C000072749        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.18% 2.27%   3.11%
Without Sales Load [Member] | C000072750        
Average Annual Return [Line Items]        
Average Annual Return, Percent 5.89% 1.96%   2.82%
Without Sales Load [Member] | C000169957        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.36% 2.42% 3.48%  
Bloomberg Global Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.03% (1.35%)   0.94%
Bloomberg Global Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.03% (1.35%)   0.94%
Bloomberg Global Aggregate Bond Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 7.03% (1.35%) 0.56%  
Bloomberg Global Aggregate Bond USD Hedged Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.06% 0.17%   2.11%
Bloomberg Global Aggregate Bond USD Hedged Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.06% 0.17%   2.11%
Bloomberg Global Aggregate Bond USD Hedged Index        
Average Annual Return [Line Items]        
Average Annual Return, Percent 6.06% 0.17% 1.95%