v3.26.1
Shareholder Report, Average Annual Return (Details)
12 Months Ended 60 Months Ended 120 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Jun. 30, 2026
C000132936 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Hedged Equity Fund (Investor Class/(MRIEX))    
Average Annual Return, Percent 6.41% 5.50% 13.85%
C000156527 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Hedged Equity Fund (Class C/(MRCEX))    
Average Annual Return, Percent 5.35% 4.53% 12.96%
C000132937 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Hedged Equity Fund (Class A/(MRAEX))    
Average Annual Return, Percent [1] 0.06% 3.93% 12.86%
C000003881 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Hedged Equity Fund (Legacy Class/(MEIFX))    
Average Annual Return, Percent 6.41% 5.48% 13.89%
C000003882 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Legacy Class/(MERDX))    
Average Annual Return, Percent 7.32% (2.36%) 7.63%
C000132941 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Institutional Class/(MRRGX))    
Average Annual Return, Percent 7.40% (2.32%) 7.67%
C000132940 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Class A/(MRAGX))    
Average Annual Return, Percent [2] 0.87% (3.73%) 6.71%
C000156528 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Class C/(MRCGX))    
Average Annual Return, Percent 6.23% (3.29%) 6.57%
C000132939 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Investor Class/(MRIGX))    
Average Annual Return, Percent 7.24% (2.42%) 7.58%
C000132942 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Contrarian Fund (Investor Class/(MFCIX))    
Average Annual Return, Percent 29.73% 8.38% 13.83%
C000156529 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Contrarian Fund (Class C/(MFCCX))    
Average Annual Return, Percent 28.43% 7.29% 12.75%
C000132943 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Contrarian Fund (Class A/(MFCAX))    
Average Annual Return, Percent [3] 22.11% 6.86% 12.88%
C000003883 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Contrarian Fund (Legacy Class/(MVALX))    
Average Annual Return, Percent 29.81% 8.42% 13.93%
C000132293 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Legacy Class/(MSGGX))    
Average Annual Return, Percent 17.09% (0.32%) 9.37%
C000132296 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Institutional Class/(MSGRX))    
Average Annual Return, Percent 17.25% (0.20%) 9.49%
C000132295 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Class A/(MSGAX))    
Average Annual Return, Percent [4] 10.12% (1.78%) 8.39%
C000156530 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Class C/(MSGCX))    
Average Annual Return, Percent 15.94% (1.33%) 8.26%
C000132294 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Investor Class/(MISGX))    
Average Annual Return, Percent 17.03% (0.35%) 9.32%
Without Sales Load [Member] | C000132937 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Hedged Equity Fund (Class A/(MRAEX))    
Average Annual Return, Percent 6.16% 5.17% 13.53%
Without Sales Load [Member] | C000132940 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Growth Fund (Class A/(MRAGX))    
Average Annual Return, Percent 7.01% (2.58%) 7.34%
Without Sales Load [Member] | C000132943 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Contrarian Fund (Class A/(MFCAX))    
Average Annual Return, Percent 29.57% 8.13% 13.55%
Without Sales Load [Member] | C000132295 [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Meridian Small Cap Growth Fund (Class A/(MSGAX))    
Average Annual Return, Percent 16.80% (0.61%) 9.04%
CBOE S And P 500 Buy Write Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name CBOE S&P 500 Buy Write Index    
Average Annual Return, Percent 17.34% 8.39% 7.72%
Standard & Poor's 500 Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name S&P 500® Index    
Average Annual Return, Percent 22.33% 13.41% 15.51%
Russell 3000 Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 3000® Index    
Average Annual Return, Percent 22.82% 12.31% 15.06%
Russell 2500 Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 2500® Index    
Average Annual Return, Percent 36.72% 8.30% 12.25%
Russell 2500 Growth Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 2500® Growth Index    
Average Annual Return, Percent 32.94% 4.98% 12.56%
Russell 2500 Value Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 2500® Value Index    
Average Annual Return, Percent 38.54% 10.28% 11.28%
Russell 2000 Growth Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 2000® Growth Index    
Average Annual Return, Percent 38.74% 5.57% 11.97%
[1]
Assuming maximum sales charge, if any.  Class A Shares are subject to a maximum initial sales charge of 5.75%
[2]
Assuming maximum sales charge, if any.  Class A Shares are subject to a maximum initial sales charge of 5.75%
[3]
Assuming maximum sales charge, if any.  Class A Shares are subject to a maximum initial sales charge of 5.75%
[4]
Assuming maximum sales charge, if any.  Class A Shares are subject to a maximum initial sales charge of 5.75%