Notes Payable (Schedule of Long-term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Notes Payable [Abstract]
Secured Debt, Other	$ 120,000		$ 120,000
Secured loan	20,000		20,000
Unsecured credit facility	150,000	[1]	50,000	[1]
Notes Payable	$ 290,000		$ 190,000

[1] On July 2, 2013, the Company entered into an unsecured $200 million five-year revolving credit facility. The interest rate on borrowings under the credit facility is based on the Company's debt to total capital ratio and ranges from LIBOR plus 112.5 basis points when the ratio is under 15% to LIBOR plus 162.5 basis points when the ratio is above 25%. Commitment fees for the undrawn portions of the credit facility range from 12.5 basis points when the ratio is under 15% to 22.5 basis points when the ratio is above 25%. Effective December 3, 2014, the Company extended the maturity date of the unsecured credit facility from June 30, 2018 to December 3, 2019, and expanded the borrowing capacity from $200 million to $250 million. In 2014, the interest rate was LIBOR plus 112.5 basis points on the $150 million of borrowings and 12.5 basis points on the undrawn portions of the credit facility.