Investments in Equity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 156,443	$ 160,295
Gross Unrealized, Gains	12,022	20,314
Gross Unrealized, Losses	(14,952)	(9,618)
Carrying and fair value of equity securities	153,513	170,991
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	69,860	69,870
Gross Unrealized, Gains	0	11,929
Gross Unrealized, Losses	(10,669)	(5,453)
Carrying and fair value of equity securities	59,191	76,346
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	86,583	90,425
Gross Unrealized, Gains	12,022	8,385
Gross Unrealized, Losses	(4,283)	(4,165)
Carrying and fair value of equity securities	$ 94,322	$ 94,645