Shareholder Report, Holdings (Details)	Jun. 30, 2025
C000017151 \| NVIDIA Corp.
Holdings [Line Items]
Percent of Net Asset Value	7.30%
C000017151 \| Microsoft Corp.
Holdings [Line Items]
Percent of Net Asset Value	7.00%
C000017151 \| Apple, Inc.
Holdings [Line Items]
Percent of Net Asset Value	5.80%
C000017151 \| Amazon.com, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.90%
C000017151 \| Alphabet, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.50%
C000017151 \| Meta Platforms, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.00%
C000017151 \| Broadcom, Inc.
Holdings [Line Items]
Percent of Net Asset Value	2.40%
C000017151 \| Berkshire Hathaway, Inc.
Holdings [Line Items]
Percent of Net Asset Value	1.70%
C000017151 \| Tesla, Inc.
Holdings [Line Items]
Percent of Net Asset Value	1.70%
C000017151 \| JPMorgan Chase & Co.
Holdings [Line Items]
Percent of Net Asset Value	1.50%
C000017151 \| SectorInformation Technology
Holdings [Line Items]
Percent of Net Asset Value	33.00%
C000017151 \| SectorFinancials
Holdings [Line Items]
Percent of Net Asset Value	14.00%
C000017151 \| SectorConsumer Discretionary
Holdings [Line Items]
Percent of Net Asset Value	10.00%
C000017151 \| SectorCommunication Services
Holdings [Line Items]
Percent of Net Asset Value	10.00%
C000017151 \| SectorHealth Care
Holdings [Line Items]
Percent of Net Asset Value	9.00%
C000017151 \| SectorIndustrials
Holdings [Line Items]
Percent of Net Asset Value	9.00%
C000017151 \| SectorConsumer Staples
Holdings [Line Items]
Percent of Net Asset Value	5.00%
C000017151 \| SectorEnergy
Holdings [Line Items]
Percent of Net Asset Value	3.00%
C000017151 \| SectorUtilities
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017151 \| SectorReal Estate
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017151 \| SectorMaterials
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017151 \| AssetCommon Stocks
Holdings [Line Items]
Percent of Net Asset Value	99.00%
C000017151 \| AssetCash Equivalents
Holdings [Line Items]
Percent of Net Asset Value	1.00%
C000017151 \| AssetGovernment & Agency Obligations
Holdings [Line Items]
Percent of Net Asset Value	0.00%
C000017151 \| Asset Other Net Line
Holdings [Line Items]
Percent of Net Asset Value	0.00%
C000017152 \| NVIDIA Corp.
Holdings [Line Items]
Percent of Net Asset Value	7.30%
C000017152 \| Microsoft Corp.
Holdings [Line Items]
Percent of Net Asset Value	7.00%
C000017152 \| Apple, Inc.
Holdings [Line Items]
Percent of Net Asset Value	5.80%
C000017152 \| Amazon.com, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.90%
C000017152 \| Alphabet, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.50%
C000017152 \| Meta Platforms, Inc.
Holdings [Line Items]
Percent of Net Asset Value	3.00%
C000017152 \| Broadcom, Inc.
Holdings [Line Items]
Percent of Net Asset Value	2.40%
C000017152 \| Berkshire Hathaway, Inc.
Holdings [Line Items]
Percent of Net Asset Value	1.70%
C000017152 \| Tesla, Inc.
Holdings [Line Items]
Percent of Net Asset Value	1.70%
C000017152 \| JPMorgan Chase & Co.
Holdings [Line Items]
Percent of Net Asset Value	1.50%
C000017152 \| SectorInformation Technology
Holdings [Line Items]
Percent of Net Asset Value	33.00%
C000017152 \| SectorFinancials
Holdings [Line Items]
Percent of Net Asset Value	14.00%
C000017152 \| SectorConsumer Discretionary
Holdings [Line Items]
Percent of Net Asset Value	10.00%
C000017152 \| SectorCommunication Services
Holdings [Line Items]
Percent of Net Asset Value	10.00%
C000017152 \| SectorHealth Care
Holdings [Line Items]
Percent of Net Asset Value	9.00%
C000017152 \| SectorIndustrials
Holdings [Line Items]
Percent of Net Asset Value	9.00%
C000017152 \| SectorConsumer Staples
Holdings [Line Items]
Percent of Net Asset Value	5.00%
C000017152 \| SectorEnergy
Holdings [Line Items]
Percent of Net Asset Value	3.00%
C000017152 \| SectorUtilities
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017152 \| SectorReal Estate
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017152 \| SectorMaterials
Holdings [Line Items]
Percent of Net Asset Value	2.00%
C000017152 \| AssetCommon Stocks
Holdings [Line Items]
Percent of Net Asset Value	99.00%
C000017152 \| AssetCash Equivalents
Holdings [Line Items]
Percent of Net Asset Value	1.00%
C000017152 \| AssetGovernment & Agency Obligations
Holdings [Line Items]
Percent of Net Asset Value	0.00%
C000017152 \| Asset Other Net Line
Holdings [Line Items]
Percent of Net Asset Value	0.00%