Other Investments - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Schedule Of Held To Maturity Securities [Line Items]
Debt security, held-to-maturity	$ 15,000	[1]	$ 15,000	[1]
Equity investment in non-public repurchase lending counterparty	6,000		6,000
Maturity date	Mar. 24, 2019
Debt security bears interest at the rate	The debt security pays interest quarterly at the rate of 4.0% above the three-month London Interbank Offered Rate (“LIBOR”).
Debt security, held-to-maturity, fair value	$ 14,926	[1]	$ 14,853	[1]
London Interbank Offered Rate (LIBOR)
Schedule Of Held To Maturity Securities [Line Items]
Debt security, variable rate basis added to LIBOR to determine interest rate	4.00%

[1] Included in other investments on the consolidated balance sheets.