Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Contractual commitments to invest in limited partnership investments
Represents the entity's maximum contractual commitments to invest in its limited partnership investments	$ 16.9
Description of commitment: contractual commitment to invest in limited partnership investments	Contractual commitments to invest in limited partnership investments, consisting of private equity securities, mezzanine debt securities, and real estate activities.
Private equity
Contractual commitments to invest in limited partnership investments
Represents the entity's maximum contractual commitments to invest in its limited partnership investments	$ 6.8
Mezzanine debt
Contractual commitments to invest in limited partnership investments
Represents the entity's maximum contractual commitments to invest in its limited partnership investments	8.2
Real estate
Contractual commitments to invest in limited partnership investments
Represents the entity's maximum contractual commitments to invest in its limited partnership investments	$ 1.9