MFS Series Trust Xiii N-CSR 28 Oct 24 Certified annual shareholder report (management investment company) Financial data

Form N-CSR Cover

Form N-CSR Cover	12 Months Ended
	Aug. 31, 2024
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	MFS SERIES TRUST XIII
Entity Central Index Key	0000356349
Document Period End Date	Aug. 31, 2024

Shareholder Report

Shareholder Report	12 Months Ended
	Aug. 31, 2024 USD ($) Holding
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	MFS SERIES TRUST XIII
Entity Central Index Key	0000356349
Document Period End Date	Aug. 31, 2024
C000074269 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class A
Trading Symbol	MGLAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment A $ 1.19 %
Expenses Paid, Amount	$ 128
Expense Ratio, Percent	1.19%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class A shares of the MFS Global Real Estate Fund (fund) provided a total return of 14.78%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment This graph shows the performance of a hypothetical $10,000 investment in Class A over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr 10-yr A without sales charge 14.78 % 3.26 % 5.24 % A with initial sales charge (5.75%) 8.18 % 2.05 % 4.62 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 8.78 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.09 % + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/a
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[1]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074270 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class B
Trading Symbol	MGLDX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment B $ 1.94 %
Expenses Paid, Amount	$ 208
Expense Ratio, Percent	1.94%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class B shares of the MFS Global Real Estate Fund (fund) provided a total return of 13.92%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class B over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* B without sales charge 13.92 % 2.49 % 4.60 % B with CDSC (declining over six years from 4% to 0%) × 9.92 % 2.13 % 4.60 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc. × Assuming redemption at the end of the applicable period. CDSC – Contingent Deferred Sales Charge.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/b
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[2]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074271 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class C
Trading Symbol	MGLCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment C $ 1.94 %
Expenses Paid, Amount	$ 207
Expense Ratio, Percent	1.94%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class C shares of the MFS Global Real Estate Fund (fund) provided a total return of 13.91%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class C over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* C without sales charge 13.91 % 2.49 % 4.60 % C with CDSC (1% for 12 months) × 12.91 % 2.49 % 4.60 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc. × Assuming redemption at the end of the applicable period. CDSC – Contingent Deferred Sales Charge.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/c
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[3]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074272 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class I
Trading Symbol	MGLIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment I $ 0.94 %
Expenses Paid, Amount	$ 101
Expense Ratio, Percent	0.94%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class I shares of the MFS Global Real Estate Fund (fund) provided a total return of 15.09%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment This graph shows the performance of a hypothetical $10,000 investment in Class I over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr 10-yr I without sales charge 15.09 % 3.52 % 5.49 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 8.78 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.09 % + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/i
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[4]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074273 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class R1
Trading Symbol	MGLJX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R1 $ 1.94 %
Expenses Paid, Amount	$ 207
Expense Ratio, Percent	1.94%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class R1 shares of the MFS Global Real Estate Fund (fund) provided a total return of 13.88%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class R1 over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* R1 without sales charge 13.88 % 2.48 % 4.60 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/r1
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[5]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074274 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class R2
Trading Symbol	MGLKX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R2 $ 1.44 %
Expenses Paid, Amount	$ 154
Expense Ratio, Percent	1.44%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class R2 shares of the MFS Global Real Estate Fund (fund) provided a total return of 14.46%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class R2 over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* R2 without sales charge 14.46 % 2.99 % 5.12 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/r2
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[6]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074275 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class R3
Trading Symbol	MGLLX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R3 $ 1.19 %
Expenses Paid, Amount	$ 128
Expense Ratio, Percent	1.19%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class R3 shares of the MFS Global Real Estate Fund (fund) provided a total return of 14.75%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class R3 over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* R3 without sales charge 14.75 % 3.25 % 5.39 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/r3
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[7]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000074276 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class R4
Trading Symbol	MGLMX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R4 $ 0.94 %
Expenses Paid, Amount	$ 101
Expense Ratio, Percent	0.94%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class R4 shares of the MFS Global Real Estate Fund (fund) provided a total return of 15.00%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment* This graph shows the performance of a hypothetical $10,000 investment in Class R4 over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr Life* R4 without sales charge 15.00 % 3.53 % 5.65 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 9.43 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.17 % * For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024. + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
Performance Inception Date	Dec. 19, 2014
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/r4
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[8]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
C000117929 [Member]
Shareholder Report [Line Items]
Fund Name	MFS® Global Real Estate Fund
Class Name	Class R6
Trading Symbol	MGLRX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about MFS Global Real Estate Fund for the period of September 1, 2023 to August 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the fund at funds.mfs.com
Additional Information Phone Number	1‑800‑225‑2606
Additional Information Email	orderliterature@mfs.com
Additional Information Website	funds.mfs.com
Expenses [Text Block]	FUND EXPENSES What were the fund costs for the last year? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment R6 $ 0.85 %
Expenses Paid, Amount	$ 91
Expense Ratio, Percent	0.85%
Factors Affecting Performance [Text Block]	MANAGEMENT'S DISCUSSION OF FUND PERFORMANCE For the twelve months ended August 31, 2024, Class R6 shares of the MFS Global Real Estate Fund (fund) provided a total return of 15.13%, at net asset value. This compares with a return of 23.44% for the fund’s benchmark, the MSCI All Country World Index (net div). The fund's other benchmark, the FTSE EPRA Nareit Developed Real Estate Index (net div), generated a return of 17.45%. As inflation moderated around the globe during the reporting period, several major central banks began to ease monetary policy. Geopolitical strains remained high amid ongoing conflicts in Ukraine and in the Middle East, while relations between China and the US remained tense. The US sought to restrict the flow of advanced technologies to China and China looked to use its industrial overcapacity to increase exports to developed markets to bolster its slow-growing domestic economy. Toward the end of the period, labor markets, particularly in the US, loosened modestly, brightening the inflation outlook. Global equity markets reached record levels during the period as they withstood the adversity of the unsettled geopolitical climate and higher interest rate environment amidst optimism over wide-scale adoption of artificial intelligence. Top contributors to performance relative to the FTSE EPRA Nareit Developed Real Estate Index: The fund's underweight position in real estate investments within Hong Kong contributed to relative performance. Security selection within Australia further aided relative returns. Top detractors from performance relative to the FTSE EPRA Nareit Developed Real Estate Index: Security selection within the United States detracted from relative performance. During the reporting period, the fund's relative currency exposure, resulting primarily from differences between the fund's and the benchmark's exposures to holdings of securities denominated in foreign currencies, was another detractor from relative performance.
Performance Past Does Not Indicate Future [Text]	The fund’s past performance is not a good predictor of the fund’s future performance.
Line Graph [Table Text Block]	FUND PERFORMANCE The fund’s past performance is not a good predictor of the fund’s future performance. Growth of a Hypothetical $10,000 Investment This graph shows the performance of a hypothetical $10,000 investment in Class R6 over a ten year period or since inception, if shorter, in comparison to (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests. This graph includes the deduction of the maximum applicable sales charge, if any.
Average Annual Return [Table Text Block]	Average Annual Total Returns through 8/31/24 This table shows the average annual total returns of the class of shares noted for the periods shown, both with (if any) and without sales charges. It also shows the average annual total returns of (i) a broad measure of market performance and (ii) an additional index that MFS believes more closely reflects the market segments in which the fund invests, over the same periods. Share Class 1-yr 5-yr 10-yr R6 without sales charge 15.13 % 3.61 % 5.58 % Comparative Benchmark(s) MSCI All Country World Index (net div) +∆ 23.44 % 12.14 % 8.78 % FTSE EPRA Nareit Developed Real Estate Index (net div) +∆ 17.45 % 1.26 % 3.09 % + Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests. ∆ Source: FactSet Research Systems Inc.
No Deduction of Taxes [Text Block]	The graph and table below do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
Performance Table Market Index Changed [Text Block]	Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.
Updated Performance Information Location [Text Block]	Visit mfs.com/perf/r6
Net Assets	$ 2,503,453,782
Holdings Count | Holding	51
Advisory Fees Paid, Amount	$ 18,936,661	[9]
Investment Company Portfolio Turnover	48%
Additional Fund Statistics [Text Block]	FUND STATISTICS AS OF 8/31/24 Net Assets ($): 2,503,453,782 Total Management Fee ($)#: 18,936,661 Total Number of Holdings: 51 Portfolio Turnover Rate (%): 48 # Where the fund holds derivatives, they are not included in the total number of portfolio holdings.
Holdings [Text Block]	PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 8/31/24) Portfolio structure Equities 98.9 % Money Market Funds 1.1 % Equity sectors Real Estate 94.2 % Communication Services 3.1 % Health Care 1.6 % Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 % Issuer country weightings United States 68.9 % United Kingdom 8.1 % Japan 5.7 % Australia 5.7 % Singapore 2.7 % Germany 2.2 % Canada 1.8 % Belgium 1.7 % Spain 1.6 % Other Countries 1.6 % MFS uses the Global Industry Classification Standard (GICS ®
Largest Holdings [Text Block]	Top ten holdings Prologis, Inc., REIT 9.3 % Equinix, Inc., REIT 6.1 % Extra Space Storage, Inc., REIT 4.6 % Goodman Group, REIT 4.1 % Mid-America Apartment Communities, Inc., REIT 4.1 % Mitsui Fudosan Co. Ltd. 3.6 % Equity Lifestyle Properties, Inc., REIT 3.5 % Digital Realty Trust, Inc., REIT 3.2 % Ventas, Inc., REIT 3.1 % Sun Communities, Inc., REIT 2.8 %
[1]Includes the effect of any management fee waivers.[2]Includes the effect of any management fee waivers.[3]Includes the effect of any management fee waivers.[4]Includes the effect of any management fee waivers.[5] #

Shareholder Report, Line Graph

Shareholder Report, Line Graph (Details) - USD ($)		12 Months Ended		60 Months Ended		116 Months Ended		120 Months Ended
		Aug. 31, 2024		Aug. 31, 2024		Aug. 31, 2024		Aug. 31, 2024		Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015	Dec. 19, 2014	Aug. 31, 2014
C000074269 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		A with initial sales charge (5.75%)
Average Annual Return, Percent		8.18%		2.05%				4.62%
C000074269 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		A without sales charge
Account Value		$ 15,704		$ 15,704		$ 15,704		$ 15,704		$ 13,682	$ 14,365	$ 17,429	$ 13,102	$ 13,375	$ 11,917	$ 11,117	$ 10,760	$ 9,032		$ 9,425
Average Annual Return, Percent		14.78%		3.26%				5.24%
C000074270 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		B with CDSC (declining over six years from 4% to 0%)
Average Annual Return, Percent	[1]	9.92%		2.13%		4.60%	[2]
C000074270 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		B without sales charge
Account Value		$ 15,473		$ 15,473		$ 15,473		$ 15,473		13,582	14,363	17,556	13,298	13,680	12,273	11,531	11,254	9,517	$ 10,000
Average Annual Return, Percent		13.92%		2.49%		4.60%	[2]
C000074271 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		C with CDSC (1% for 12 months)
Average Annual Return, Percent	[3]	12.91%		2.49%		4.60%	[4]
C000074271 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		C without sales charge
Account Value		$ 15,467		$ 15,467		$ 15,467		15,467		13,578	14,361	17,554	13,289	13,674	12,271	11,524	11,249	9,507	10,000
Average Annual Return, Percent		13.91%		2.49%		4.60%	[4]
C000074272 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		I without sales charge
Account Value		$ 17,067		$ 17,067		$ 17,067		$ 17,067		14,830	15,539	18,794	14,098	14,357	12,752	11,865	11,462	9,601		10,000
Average Annual Return, Percent		15.09%		3.52%				5.49%
C000074273 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		R1 without sales charge
Account Value		$ 15,467		$ 15,467		$ 15,467		$ 15,467		13,582	14,371	17,558	13,299	13,682	12,277	11,544	11,260	9,517	10,000
Average Annual Return, Percent		13.88%		2.48%		4.60%	[5]
C000074274 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		R2 without sales charge
Account Value		$ 16,238		$ 16,238		$ 16,238		16,238		14,186	14,937	18,163	13,686	14,011	12,510	11,700	11,349	9,543	10,000
Average Annual Return, Percent		14.46%		2.99%		5.12%	[6]
C000074275 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		R3 without sales charge
Account Value		$ 16,638		$ 16,638		$ 16,638		16,638		14,499	15,230	18,467	13,880	14,176	12,632	11,772	11,403	9,568	10,000
Average Annual Return, Percent		14.75%		3.25%		5.39%	[7]
C000074276 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		R4 without sales charge
Account Value		$ 17,036		$ 17,036		$ 17,036		17,036		14,814	15,508	18,766	14,071	14,327	12,739	11,853	11,447	9,582	10,000
Average Annual Return, Percent		15%		3.53%		5.65%	[8]
C000117929 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		R6 without sales charge
Account Value		$ 17,208		$ 17,208		$ 17,208		$ 17,208		14,947	15,633	18,905	14,162	14,415	12,793	11,892	11,477	9,601		10,000
Average Annual Return, Percent		15.13%		3.61%				5.58%
MSCI All Country World Index net div [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		MSCI All Country World Index (net div)
Account Value		$ 23,192		$ 23,192		$ 23,192		$ 23,192		18,788	16,488	19,601	15,237	13,077	13,113	11,770	10,050	9,371	10,000	10,000
Average Annual Return, Percent		23.44%	[9],[10]	12.14%	[9],[10]	9.43%	[2],[11],[12]	8.78%	[9],[10]
MSCI All Country World C000074273 Index net div [Member]
Account Value [Line Items]
Account Value		$ 23,981		$ 23,981		$ 23,981		$ 23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
MSCI All Country World C000074274 Index net div [Member]
Account Value [Line Items]
Account Value		23,981		23,981		23,981		23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
MSCI All Country World C000074275 Index net div [Member]
Account Value [Line Items]
Account Value		23,981		23,981		23,981		23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
MSCI All Country World C000074271 Index net div [Member]
Account Value [Line Items]
Account Value		23,981		23,981		23,981		23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
MSCI All Country World C000074270 Index net div [Member]
Account Value [Line Items]
Account Value		23,981		23,981		23,981		23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
MSCI All Country World C000074276 Index net div [Member]
Account Value [Line Items]
Account Value		$ 23,981		23,981		23,981		23,981		19,427	17,049	20,268	15,756	13,521	13,559	12,170	10,392	9,690
FTSE EPRA Nareit Developed Real Estate Index net div [Member]
Account Value [Line Items]
Line Graph and Table Measure Name		FTSE EPRA Nareit Developed Real Estate Index (net div)
Account Value		$ 13,553		$ 13,553		$ 13,553		$ 13,553		11,539	12,171	14,651	10,987	12,729	11,772	11,160	11,171	9,522	$ 10,000	$ 10,000
Average Annual Return, Percent		17.45%	[9],[10]	1.26%	[9],[10]	3.17%	[2],[11],[12]	3.09%	[9],[10]
FTSE EPRA Nareit Developed Real Estate C000074274 Index net div [Member]
Account Value [Line Items]
Account Value		$ 13,541		$ 13,541		$ 13,541		$ 13,541		11,529	12,160	14,638	10,978	12,717	11,762	11,150	11,161	9,513
FTSE EPRA Nareit Developed Real Estate C000074273 Index net div [Member]
Account Value [Line Items]
Account Value		13,541		13,541		13,541		13,541		11,529	12,160	14,638	10,978	12,717	11,762	11,150	11,161	9,513
FTSE EPRA Nareit Developed Real Estate C000074275 Index net div [Member]
Account Value [Line Items]
Account Value		13,541		13,541		13,541		13,541		11,529	12,160	14,638	10,978	12,717	11,762	11,150	11,161	9,513
FTSE EPRA Nareit Developed Real Estate C000074271 Index net div [Member]
Account Value [Line Items]
Account Value		13,541		13,541		13,541		13,541		11,529	12,160	14,638	10,978	12,717	11,762	11,150	11,161	9,513
FTSE EPRA Nareit Developed Real Estate C000074270 Index net div [Member]
Account Value [Line Items]
Account Value		13,541		13,541		13,541		13,541		11,529	12,160	14,638	10,978	12,717	11,762	11,150	11,161	9,513
FTSE EPRA Nareit Developed Real Estate C000074276 Index net div [Member]
Account Value [Line Items]
Account Value		$ 13,541		$ 13,541		$ 13,541		$ 13,541		$ 11,529	$ 12,160	$ 14,638	$ 10,978	$ 12,717	$ 11,762	$ 11,150	$ 11,161	$ 9,513
[1]Assuming redemption at the end of the applicable period.[2]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[3]Assuming redemption at the end of the applicable period.[4]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[5]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[6]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[7]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[8]For the period from the commencement of the class's investment operations, December 19, 2014 through August 31, 2024.[9]Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.[10]Source: FactSet Research Systems Inc.[11]Effective May 1, 2024, the MSCI All Country World Index (net div) replaced the FTSE EPRA Nareit Developed Real Estate Index (net div) as a broad measure of market performance in accordance with new regulatory disclosure requirements. The fund continues to use the FTSE EPRA Nareit Developed Real Estate Index (net div) as an additional benchmark that MFS believes more closely reflects the market segments in which the fund invests.[12]Source: FactSet Research Systems Inc.

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Aug. 31, 2024
C000074269 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074269 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074269 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074269 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074269 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074269 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074269 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074269 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074269 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074269 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074269 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074269 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074269 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074269 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074269 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074269 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074269 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074269 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074269 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074269 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074269 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074269 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074269 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074269 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074269 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074270 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074270 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074270 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074270 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074270 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074270 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074270 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074270 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074270 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074270 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074270 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074270 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074270 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074270 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074270 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074270 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074270 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074270 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074270 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074270 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074270 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074270 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074270 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074270 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074270 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074271 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074271 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074271 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074271 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074271 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074271 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074271 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074271 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074271 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074271 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074271 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074271 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074271 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074271 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074271 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074271 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074271 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074271 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074271 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074271 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074271 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074271 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074271 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074271 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074271 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074272 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074272 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074272 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074272 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074272 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074272 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074272 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074272 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074272 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074272 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074272 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074272 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074272 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074272 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074272 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074272 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074272 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074272 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074272 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074272 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074272 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074272 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074272 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074272 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074272 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074273 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074273 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074273 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074273 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074273 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074273 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074273 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074273 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074273 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074273 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074273 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074273 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074273 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074273 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074273 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074273 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074273 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074273 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074273 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074273 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074273 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074273 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074273 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074273 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074273 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074274 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074274 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074274 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074274 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074274 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074274 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074274 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074274 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074274 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074274 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074274 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074274 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074274 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074274 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074274 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074274 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074274 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074274 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074274 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074274 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074274 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074274 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074274 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074274 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074274 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074275 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074275 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074275 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074275 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074275 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074275 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074275 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074275 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074275 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074275 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074275 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074275 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074275 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074275 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074275 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074275 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074275 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074275 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074275 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074275 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074275 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074275 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074275 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074275 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074275 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000074276 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000074276 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000074276 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000074276 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074276 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000074276 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000074276 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000074276 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000074276 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074276 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000074276 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074276 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074276 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000074276 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000074276 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074276 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000074276 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000074276 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000074276 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000074276 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000074276 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000074276 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000074276 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000074276 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000074276 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%
C000117929 [Member] | Prologis Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	9.30%
C000117929 [Member] | Equinix Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	6.10%
C000117929 [Member] | Extra Space Storage Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.60%
C000117929 [Member] | Goodman Group REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000117929 [Member] | Mid America Apartment Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	4.10%
C000117929 [Member] | Mitsui Fudosan Co Ltd [Member]
Holdings [Line Items]
Percent of Total Investments	3.60%
C000117929 [Member] | Equity Lifestyle Properties Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.50%
C000117929 [Member] | Digital Realty Trust Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.20%
C000117929 [Member] | Ventas Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000117929 [Member] | Sun Communities Inc REIT [Member]
Holdings [Line Items]
Percent of Total Investments	2.80%
C000117929 [Member] | Other Countries [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000117929 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Total Investments	1.60%
C000117929 [Member] | Real Estate Sector [Member]
Holdings [Line Items]
Percent of Total Investments	94.20%
C000117929 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Total Investments	3.10%
C000117929 [Member] | AUSTRALIA
Holdings [Line Items]
Percent of Total Investments	5.70%
C000117929 [Member] | BELGIUM
Holdings [Line Items]
Percent of Total Investments	1.70%
C000117929 [Member] | CANADA
Holdings [Line Items]
Percent of Total Investments	1.80%
C000117929 [Member] | GERMANY
Holdings [Line Items]
Percent of Total Investments	2.20%
C000117929 [Member] | SPAIN
Holdings [Line Items]
Percent of Total Investments	1.60%
C000117929 [Member] | UNITED KINGDOM
Holdings [Line Items]
Percent of Total Investments	8.10%
C000117929 [Member] | JAPAN
Holdings [Line Items]
Percent of Total Investments	5.70%
C000117929 [Member] | SINGAPORE
Holdings [Line Items]
Percent of Total Investments	2.70%
C000117929 [Member] | UNITED STATES
Holdings [Line Items]
Percent of Total Investments	68.90%
C000117929 [Member] | Equity [Member]
Holdings [Line Items]
Percent of Total Investments	98.90%
C000117929 [Member] | Money Market Funds [Member]
Holdings [Line Items]
Percent of Total Investments	1.10%