Investment Securities Available for Sale (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Market Value	$ 152,700		$ 181,976
In loss position for Less than 12 months, Fair Value	5,762		15,991
In loss position for Less than 12 months, Unrealized Losses	(238)		(77)
In loss position for 12 months or more, Fair Value	0		0
In loss position for 12 months or more, Unrealized Losses	0		0
Total Fair Value	5,762		15,991
Total Unrealized Losses	(238)		(77)
Gross realized gains on sales	759	$ 13,564
Gross realized losses on other-than-temporary impairments	(192)	(535)
Total net	567	13,029
Proceeds from investment securities sales	51,218	74,591
Proceeds from early redemptions by issuers	2,517	2,541
Gross realized losses on other-than-temporary impairments	(4,813)	$ 0
Marketable equity securities
Schedule of Available-for-sale Securities [Line Items]
Market Value	56,531		67,273
In loss position for Less than 12 months, Fair Value	5,762		5,938
In loss position for Less than 12 months, Unrealized Losses	(238)		(62)
In loss position for 12 months or more, Fair Value	0		0
In loss position for 12 months or more, Unrealized Losses	0		0
Total Fair Value	5,762		5,938
Total Unrealized Losses	(238)		(62)
Mutual funds invested in fixed income securities
Schedule of Available-for-sale Securities [Line Items]
Market Value	20,292		20,111
In loss position for Less than 12 months, Fair Value			10,053
In loss position for Less than 12 months, Unrealized Losses			(15)
In loss position for 12 months or more, Fair Value			0
In loss position for 12 months or more, Unrealized Losses			0
Total Fair Value			10,053
Total Unrealized Losses			$ (15)
U.S. Government securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	0
1 Year up to 5 Years	22,730
More than 5 Years	0
Market Value	22,730
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	433
1 Year up to 5 Years	35,159
More than 5 Years	0
Market Value	35,592
U.S. mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	605
1 Year up to 5 Years	4,764
More than 5 Years	0
Market Value	5,369
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	4,526
1 Year up to 5 Years	1,079
More than 5 Years	0
Market Value	5,605
U.S. asset backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	3,857
1 Year up to 5 Years	586
More than 5 Years	0
Market Value	4,443
Index-linked U.S. bonds
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	0
1 Year up to 5 Years	2,138
More than 5 Years	0
Market Value	2,138
Marketable debt securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	9,421
1 Year up to 5 Years	66,456
More than 5 Years	0
Market Value	75,877
Chief Executive Officer [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross realized losses on other-than-temporary impairments	$ (4,772)