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, 2019 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	$ 500,614
Unfunded commitments	22,140
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	265,263
Unfunded commitments	10,579
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	64,600
Unfunded commitments	$ 4,000
Non-marketable securities | Fair value accounting | Lower Limit | Consolidated venture capital and private equity fund investments
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 | Consolidated venture capital and private equity fund investments
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	$ 215,367
Unfunded commitments	10,675
Non-marketable securities | Equity method accounting | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	12,713
Unfunded commitments	$ 886
Non-marketable securities | Equity method accounting | Lower Limit | Other investments
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 | Other investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated future period of distributions from the fund investments	8 years