S000031344 [Member] Average Annual Total Returns	12 Months Ended	60 Months Ended	120 Months Ended	135 Months Ended	158 Months Ended	183 Months Ended	287 Months Ended
S000031344 [Member] Average Annual Total Returns	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Bloomberg U.S. Mortgage-Backed Securities Index (reflects no deductions for fees, expenses or taxes)
Prospectus [Line Items]
Average Annual Return, Percent	8.58%	0.15%	1.59%
Bloomberg U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)
Prospectus [Line Items]
Average Annual Return, Percent	7.30%	(0.36%)	2.01%
C000121134 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	9.58%	(0.59%)	1.74%
Performance Inception Date					Nov. 08, 2012
C000149222 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	9.66%	(0.54%)	1.81%
Performance Inception Date				Oct. 01, 2014
C000097356 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	6.00%	(1.52%)	1.09%
Performance Inception Date							Feb. 14, 2002
C000097356 [Member] \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent	4.26%	(2.82%)	(0.17%)
Performance Inception Date							Feb. 14, 2002
C000097356 [Member] \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent	3.53%	(1.70%)	0.29%
Performance Inception Date							Feb. 14, 2002
C000097358 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	7.46%	(1.66%)	0.64%
Performance Inception Date							Feb. 14, 2002
C000097361 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	9.49%	(0.68%)	1.65%
Performance Inception Date						Sep. 27, 2010