v3.26.1
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 60 Months Ended 120 Months Ended
May 31, 2026
May 31, 2026
May 31, 2026
Without Sales Load [Member] | C000072749      
Average Annual Return [Line Items]      
Average Annual Return, Percent 5.65% 1.36% 3.40%
Without Sales Load [Member] | C000072750      
Average Annual Return [Line Items]      
Average Annual Return, Percent 5.35% 1.08% 3.11%
Without Sales Load [Member] | C000169957      
Average Annual Return [Line Items]      
Average Annual Return, Percent 5.82% 1.52% 3.57%
Bloomberg Global Aggregate Bond Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.26% (1.58%) 0.74%
Bloomberg Global Aggregate Bond Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.26% (1.58%) 0.74%
Bloomberg Global Aggregate Bond Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.26% (1.58%) 0.74%
Bloomberg Global Aggregate Bond USD Hedged Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.77% 0.90% 2.08%
Bloomberg Global Aggregate Bond USD Hedged Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.77% 0.90% 2.08%
Bloomberg Global Aggregate Bond USD Hedged Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 3.77% 0.90% 2.08%