Investments (Other Investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Other Investments
Other investments	$ 80,466	$ 81,892
Investments in LPs/LLCs, at cost [Member]
Other Investments
Other investments	46,200	46,852
Convertible securities, at fair value [Member]
Other Investments
Other investments	30,814	31,501
Other, principally FHLB capital stock at cost [Member]
Other Investments
Other investments	$ 3,452	$ 3,539