Average Annual Total Returns - Classes ACS [Member]		12 Months Ended	49 Months Ended	60 Months Ended	120 Months Ended
Average Annual Total Returns - Classes ACS [Member]	Mar. 31, 2025	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2024
Bloomberg Municipal Bond Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.05%		0.99%	2.25%
Bloomberg Massachusetts Exempt Municipal Bond Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.01%		0.76%	2.01%
Class A \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent		(1.51%)		(0.40%)	1.18%
Class A \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent		0.07%		0.20%	1.51%
Class A \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		(1.51%)		(0.40%)	1.20%
Performance Inception Date	Jun. 18, 2001
Class C \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		(0.39%)		(0.58%)	0.73%
Performance Inception Date	Jun. 18, 2001
INST Class \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.62%	(0.45%)
Performance Inception Date	Dec. 01, 2020
INST Class \| Bloomberg Municipal Bond Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.05%	0.11%
INST Class \| Bloomberg Massachusetts Exempt Municipal Bond Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.01%	(0.23%)
Class S \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		1.53%		0.40%	1.74%
Performance Inception Date	May 28, 1987