Fair Value Measurements - Fair Value of Certain Investments Based on NAV (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 151,269	$ 179,417
Unfunded Commitments	27,135	31,482
Alternative Investment Funds [Member] | Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	31,837	25,110
Alternative Investment Funds [Member] | Funds of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	475	23,252
Alternative Investment Funds [Member] | Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	4,718	9,528
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 (7)%	daily (60)%
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 (20)%
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 (1)%	weekly (1)%
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 (2)%
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 (65)%	monthly (73)%
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 (92)%	monthly (39)%
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 (98)%
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 (18)%	quarterly (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] | 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] | 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] | 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	120 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	90days	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
Debt Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	4	4
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	42	9,079
% of Fair Value Not Redeemable		2.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter		2.00%
Equity Funds [Member] | Daily [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	daily (13%)	daily (37)%
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 (61)%
Equity Funds [Member] | Quarterly [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments Redeemable, Redemption Frequency	quarterly (29%)
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	120 days
Private Equity Funds [Member] | Equity Growth [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	70,054	71,068
Unfunded Commitments	27,135	31,482
% of Fair Value Not Redeemable	100.00%	100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Next 5 Years	17.00%	21.00%
Estimated Liquidation Period of Investments Not Redeemable, % 5-10 Years	60.00%	61.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	23.00%	18.00%
Private Equity Funds [Member] | Mezzanine Debt [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 44,139	$ 41,376
% of Fair Value Not Redeemable	100.00%	100.00%
Estimated Liquidation Period of Investments Not Redeemable, % Thereafter	100.00%	100.00%