Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 151,903	$ 151,269
Unfunded Commitments	27,156	27,135
Alternative Investment Funds [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	32,210	31,837
Unfunded Commitments
% of Fair Value Not Redeemable
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter
Alternative Investment Funds [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	487	475
Unfunded Commitments
% of Fair Value Not Redeemable
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter
Alternative Investment Funds [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	3,624	4,718
Unfunded Commitments
% of Fair Value Not Redeemable
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter
Alternative Investment Funds [Member] | Weekly [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	weekly (2%)	weekly (1)%
Alternative Investment Funds [Member] | Weekly [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	weekly (17%)	weekly (17)%
Alternative Investment Funds [Member] | Monthly [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	monthly (95%)	monthly (95)%
Alternative Investment Funds [Member] | Monthly [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	monthly (89%)	monthly (92)%
Alternative Investment Funds [Member] | Monthly [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	monthly (64%)	monthly (65)%
Alternative Investment Funds [Member] | Quarterly [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	quarterly (5%)	quarterly (5)%
Alternative Investment Funds [Member] | Quarterly [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	quarterly (19%)	quarterly (18)%
Alternative Investment Funds [Member] | Daily [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	daily (9%)	daily (7)%
Alternative Investment Funds [Member] | Minimum [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Alternative Investment Funds [Member] | Minimum [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Alternative Investment Funds [Member] | Minimum [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Alternative Investment Funds [Member] | Maximum [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	90 days	90 days
Alternative Investment Funds [Member] | Maximum [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	60 days	60 days
Alternative Investment Funds [Member] | Maximum [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	60 days	90 days
Debt Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	4	4
Unfunded Commitments
% of Fair Value Not Redeemable
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter
Investments Redeemable, Redemption Notice Period	30 days	30 days
Debt Funds [Member] | Daily [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	daily (100%)	daily (100)%
Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	41	42
Unfunded Commitments
% of Fair Value Not Redeemable
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter
Equity Funds [Member] | Monthly [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	monthly (58%)	monthly (58)%
Equity Funds [Member] | Quarterly [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	quarterly (28%)	quarterly (29)%
Equity Funds [Member] | Daily [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	daily (14%)	daily (13)%
Equity Funds [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	30 days	30 days
Equity Funds [Member] | Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Notice Period	90 days	90 days
Private Equity Funds [Member] | Equity Growth [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	71,408	70,054
Unfunded Commitments	27,156	27,135
% of Fair Value Not Redeemable	100.00%	100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years	14.00%	17.00%
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years	61.00%	60.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	25.00%	23.00%
Private Equity Funds [Member] | Mezzanine Debt [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	44,129	44,139
Unfunded Commitments
% of Fair Value Not Redeemable	100.00%	100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	100.00%	100.00%