Net Assets Investment Company, Portfolio Turnover C000011819 [Member] Global Equity - Advisor C000064416 [Member] Frontier Emerging Markets - Investor Class Global Equity - Institutional Class C000179659 [Member] Global Equity - Institutional Class Z C000011817 [Member] International Equity - Institutional Class C000179658 [Member] International Equity - Institutional Class Z [Member] C000011818 [Member] International Equity - Investor Class C000238190 [Member] International Developed Markets Equity - Institutional Class C000045116 [Member] International Small Companies - Institutional Class C000240396 [Member] International Small Companies - Institutional Class Z C000045117 [Member] International Small Companies - Investor Class C000011822 [Member] Institutional Emerging Markets - Institutional Class C000138298 [Member] Institutional Emerging Markets - Institutional Class Z C000064415 [Member] Frontier Emerging Markets - Institutional Class C000179660 [Member] Frontier Emerging Markets - Institutional Class Z MSCI Frontier Emerging Markets Index [Member] MSCI Emerging Markets Index [Member] MSCI ACWI ex US Small Cap Index [Member] MSCI ACWI ex US Index [Member] MSCI EAFE Index [Member] MSCI World ex US Index [Member] MSCI All Country World ex US Index [Member] MSCI All Country World Index [Member] Investment Type [Axis] Developed Market Listed [Member] Gulf States [Member] Cash on Geographical Sector [Member] Asia [Member] Europe [Member] Latin America [Member] Africa [Member] Financial Services Sector [Member] Healthcare Sector [Member] Energy Sector [Member] Cash Sector [Member] Real Estate Sector [Member] Northern Institutional Funds - Treasury Portfolio (Premier Shares) [Member] Credicorp Ltd. [Member] International Container Terminal Services Inc. [Member] Mobile World Investment Corp. [Member] Banca Transilvania SA [Member] Societe d'Exploitation des Ports [Member] NAC Kazatomprom JSC - GDR, Reg S [Member] Grupo Cibest SA - ADR [Member] Hoa Phat Group JSC [Member] Kaspi.KZ JSC - ADR [Member] China Plus Hong Kong [Member] China + Hong Kong [Member] Frontier Markets [Member] Middle East [Member] Rest of Asia [Member] All Countries [Domain] TAIWAN Taiwan KOREA, REPUBLIC OF South Korea INDIA India Taiwan Semiconductor Manufacturing Co., Ltd. [Member] Samsung Electronics Co., Ltd. - GDR, Reg S [Member] SK hynix Inc. [Member] Tencent Holdings Ltd. [Member] ASPEED Technology Inc. [Member] Delta Electronics Inc. [Member] Contemporary Amperex Technology Co., Ltd., Class A [Member] HDFC Bank Ltd. [Member] Alibaba Group Holding Ltd. [Member] Europe ex EMU [Member] Europe EMU [Member] Emerging Markets [Member] Pacific ex Japan [Member] JAPAN CANADA Clarkson plc [Member] Rubis SCA [Member] Cranswick plc [Member] KWS Saat SE And Co KGaA [Member] KWS Saat SE & Co. KGaA [Member] Silergy Corp. [Member] Diploma plc [Member] Kinaxis Inc. [Member] Artea Bankas AB [Member] Shell plc [Member] Taiwan Semiconductor Manufacturing Co., Ltd. - Sponsored ADR [Member] AIA Group Ltd. [Member] Allianz SE, Reg S [Member] Rio Tinto plc [Member] ASML Holding NV [Member] Banco Bilbao Vizcaya Argentaria SA [Member] BAE Systems plc [Member] Other Markets [Member] Manulife Financial Corp. [Member] UNITED STATES Alphabet Inc., Class A [Member] Amazon.com Inc. [Member] NVIDIA Corp. [Member] Schneider Electric SE [Member] Microsoft Corp. [Member] Meta Platforms Inc., Class A [Member] Netflix Inc. [Member]