Fair Value Disclosures (Fair Value, Investments, Entities That Calculate Net Asset Value Per Share) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value	$ 28,399	$ 26,877
Other Investment Vehicles [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value	3,717	24,043
EuroDekania [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value	3,717	4,192
Redemption frequency	N/A	N/A
Redemption notice period	N/A	N/A
EuroDekania [Member] | Other Investment Vehicles [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value	3,717	4,192
Star Asia [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value		17,104
Redemption frequency		N/A
Redemption notice period		N/A
Star Asia [Member] | Other Investment Vehicles [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value		17,104
Star Asia Special Situations Fund [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value		2,747
Unfunded commitments		321
Redemption frequency		N/A
Redemption notice period		N/A
Star Asia Special Situations Fund [Member] | Other Investment Vehicles [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other investments, at fair value		$ 2,747