Investment Securities Available for Sale (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 168,702	$ 106,649
Gross Unrealized Gains	70,787	67,348
Gross Unrealized Losses	(1,722)	(1,463)
Fair Value	237,767	172,534
Marketable equity securities
Schedule of Available-for-sale Securities [Line Items]
Cost	55,602	53,586
Gross Unrealized Gains	68,738	65,851
Gross Unrealized Losses	(1,306)	(963)
Fair Value	123,034	118,474
Mutual funds invested in fixed income securities
Schedule of Available-for-sale Securities [Line Items]
Cost	60,217
Gross Unrealized Gains	305
Gross Unrealized Losses	0
Fair Value	60,522
Marketable debt securities
Schedule of Available-for-sale Securities [Line Items]
Cost	52,883	53,063
Gross Unrealized Gains	1,744	1,497
Gross Unrealized Losses	(416)	(500)
Fair Value	$ 54,211	$ 54,060