Investments in Equity Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 161,529	$ 203,627
Gross Unrealized, Gains	64,205	86,030
Gross Unrealized, Losses	(3,710)	(6,319)
Carrying and fair value of equity securities	222,024	283,338
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	68,762	118,536
Gross Unrealized, Gains	11,742	42,239
Gross Unrealized, Losses	(531)	0
Carrying and fair value of equity securities	79,973	160,775
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	92,767	85,091
Gross Unrealized, Gains	52,463	43,791
Gross Unrealized, Losses	(3,179)	(6,319)
Carrying and fair value of equity securities	$ 142,051	$ 122,563