Investments - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Other investments, at cost	$ 15,232	$ 17,037
Maximum percentage of shareholders' equity security holdings held of one issuer	10.00%
Available-for-sale securities pledged as collateral, fair value	$ 256,100	$ 315,800
Mortgage-backed securities, weighted average life	5 years