Investments in Equity Securities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 167,964	$ 203,627
Gross Unrealized, Gains	92,100	86,030
Gross Unrealized, Losses	(3,005)	(6,319)
Carrying and fair value of equity securities	257,059	283,338
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	75,167	118,536
Gross Unrealized, Gains	28,360	42,239
Gross Unrealized, Losses	0	0
Carrying and fair value of equity securities	103,527	160,775
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	92,797	85,091
Gross Unrealized, Gains	63,740	43,791
Gross Unrealized, Losses	(3,005)	(6,319)
Carrying and fair value of equity securities	$ 153,532	$ 122,563