v3.26.3
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 59 Months Ended 60 Months Ended 90 Months Ended 120 Months Ended
Jul. 31, 2026
Jul. 31, 2026
Jul. 31, 2026
Jul. 31, 2026
Jul. 31, 2026
C000211235 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class R6) – including sales charge        
Average Annual Return, Percent 2.16%   (0.70%) 2.75%  
C000011005 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Institutional Class) – including sales charge        
Average Annual Return, Percent 2.07%   (0.78%)   2.36%
C000011004 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class R) – including sales charge        
Average Annual Return, Percent 1.56%   (1.28%)   1.87%
C000011003 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class C) – including sales charge        
Average Annual Return, Percent 0.08%   (1.75%)   1.36%
C000011001 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class A) – including sales charge        
Average Annual Return, Percent (2.77%)   (1.94%)   1.64%
C000011010 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class A) – including sales charge        
Average Annual Return, Percent (4.34%)   (5.12%)   0.43%
C000011012 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class C) – including sales charge        
Average Annual Return, Percent (1.52%)   (4.95%)   0.15%
C000011013 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class R) – including sales charge        
Average Annual Return, Percent (0.05%)   (4.48%)   0.65%
C000011014 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Institutional Class) – including sales charge        
Average Annual Return, Percent 0.50%   (3.99%)   1.16%
C000169262 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class R6) – including sales charge        
Average Annual Return, Percent 0.59%   (3.88%)   1.24%
C000228679 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class R6) – including sales charge        
Average Annual Return, Percent 5.38% 6.29%      
C000085184 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Institutional Class) – including sales charge        
Average Annual Return, Percent 5.16%   6.17%   5.23%
C000085183 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class R) – including sales charge        
Average Annual Return, Percent 4.76%   5.64%   4.71%
C000085182 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class C) – including sales charge        
Average Annual Return, Percent 3.13%   5.12%   4.19%
C000085181 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class A) – including sales charge        
Average Annual Return, Percent 2.08%   5.32%   4.69%
Without Sales Load [Member] | C000211235 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class R6) – excluding sales charge        
Average Annual Return, Percent 2.16%   (0.70%) 2.75%  
Without Sales Load [Member] | C000011005 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Institutional Class) – excluding sales charge        
Average Annual Return, Percent 2.07%   (0.78%)   2.36%
Without Sales Load [Member] | C000011004 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class R) – excluding sales charge        
Average Annual Return, Percent 1.56%   (1.28%)   1.87%
Without Sales Load [Member] | C000011003 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class C) – excluding sales charge        
Average Annual Return, Percent 1.05%   (1.75%)   1.36%
Without Sales Load [Member] | C000011001 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Corporate Bond Fund (Class A) – excluding sales charge        
Average Annual Return, Percent 1.81%   (1.02%)   2.11%
Without Sales Load [Member] | C000011010 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class A) – excluding sales charge        
Average Annual Return, Percent 0.19%   (4.23%)   0.89%
Without Sales Load [Member] | C000011012 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class C) – excluding sales charge        
Average Annual Return, Percent (0.57%)   (4.95%)   0.15%
Without Sales Load [Member] | C000011013 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class R) – excluding sales charge        
Average Annual Return, Percent (0.05%)   (4.48%)   0.65%
Without Sales Load [Member] | C000011014 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Institutional Class) – excluding sales charge        
Average Annual Return, Percent 0.50%   (3.99%)   1.16%
Without Sales Load [Member] | C000169262 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Extended Duration Bond Fund (Class R6) – excluding sales charge        
Average Annual Return, Percent 0.59%   (3.88%)   1.24%
Without Sales Load [Member] | C000228679 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class R6) – excluding sales charge        
Average Annual Return, Percent 5.38% 6.29%      
Without Sales Load [Member] | C000085184 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Institutional Class) – excluding sales charge        
Average Annual Return, Percent 5.16%   6.17%   5.23%
Without Sales Load [Member] | C000085183 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class R) – excluding sales charge        
Average Annual Return, Percent 4.76%   5.64%   4.71%
Without Sales Load [Member] | C000085182 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class C) – excluding sales charge        
Average Annual Return, Percent 4.12%   5.12%   4.19%
Without Sales Load [Member] | C000085181 [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Nomura Floating Rate Fund (Class A) – excluding sales charge        
Average Annual Return, Percent 4.90%   5.91%   4.97%
Bloomberg US Corporate Bond Index [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Bloomberg US Corporate Bond Index        
Average Annual Return, Percent 2.53%   (0.27%) 2.62% 2.27%
Bloomberg US Aggregate Index [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Bloomberg US Aggregate Index        
Average Annual Return, Percent 2.71% (0.37%) (0.40%) 1.62% 1.35%
Bloomberg Long US Corporate Index [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Bloomberg Long US Corporate Index        
Average Annual Return, Percent 0.74%   (3.51%)   1.48%
Morningstar LSTA US Leveraged Loan Index [Member]          
Average Annual Return [Line Items]          
Line Graph and Table Measure Name Morningstar LSTA US Leveraged Loan Index        
Average Annual Return, Percent 4.28% 6.19% 6.18%   5.43%