Fair Value of Financial Instruments - Summary of Estimated Fair Values of Investments and Remaining Unfunded Commitments for Each Major Category of Investments (Footnote Information) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	$ 664,482
Unfunded commitments	24,315
Non-marketable securities | Fair value accounting | Consolidated venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	273,823
Unfunded commitments	12,709
Non-marketable securities | Fair value accounting | Noncontrolling Interests | Consolidated venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	66,200
Unfunded commitments	$ 3,100
Non-marketable securities | Fair value accounting | Lower Limit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	10 years
Non-marketable securities | Fair value accounting | Upper Limit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	13 years
Non-marketable securities | Equity method accounting | Consolidated venture capital and private equity fund investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	$ 362,192
Unfunded commitments	10,509
Non-marketable securities | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	23,023
Unfunded commitments	$ 886
Non-marketable securities | Equity method accounting | Lower Limit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	5 years
Non-marketable securities | Equity method accounting | Upper Limit
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	8 years