Investment Securities Available for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 162,168	$ 238,291
Gross Unrealized Gains	19,885	34,488
Gross Unrealized Losses	(77)	(3,679)
Fair Value	181,976	269,100
Marketable equity securities
Schedule of Available-for-sale Securities [Line Items]
Cost	47,502	46,695
Gross Unrealized Gains	19,833	32,018
Gross Unrealized Losses	(62)	(1,104)
Fair Value	67,273	77,609
Mutual funds invested in fixed income securities
Schedule of Available-for-sale Securities [Line Items]
Cost	20,126	61,485
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(15)	(1,659)
Fair Value	20,111	59,826
Marketable debt securities
Schedule of Available-for-sale Securities [Line Items]
Cost	94,540	130,111
Gross Unrealized Gains	52	2,470
Gross Unrealized Losses	0	(916)
Fair Value	$ 94,592	$ 131,665