Fair Value Measurements - Investments in Company-Sponsored Funds (Details)	3 Months Ended
	Mar. 31, 2017 USD ($)
Investment Holdings [Line Items]
Fair Value	$ 7,355,000
Unfunded Commitments	1,251,000
Hedge Funds [Member]
Investment Holdings [Line Items]
Fair Value	2,662,000
Unfunded Commitments	$ 0
Redemption Frequency	Quarterly - Annually
Private Equity Funds
Investment Holdings [Line Items]
Investments Lock In Period	10 years
Fair Value	$ 4,693,000
Unfunded Commitments	1,251,000
Auction rate securities
Investment Holdings [Line Items]
Assets and liabilities transferred from level one and level two	$ 0