Investment Securities Available for Sale (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 333,883	$ 172,534
U.S. Government securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	0
1 Year up to 5 Years	44,220
More than 5 Years	0
Fair Value	44,220
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	3,480
1 Year up to 5 Years	40,031
More than 5 Years	7,402
Fair Value	50,913
U.S. mortgage backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	0
1 Year up to 5 Years	297
More than 5 Years	0
Fair Value	297
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	2,261
1 Year up to 5 Years	13,300
More than 5 Years	0
Fair Value	15,561
U.S. asset backed securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	3,980
1 Year up to 5 Years	10,691
More than 5 Years	0
Fair Value	14,671
Government agencies
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	731
1 Year up to 5 Years	2,169
More than 5 Years	0
Fair Value	2,900
Index-linked U.S. bonds
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	0
1 Year up to 5 Years	1,306
More than 5 Years	0
Fair Value	1,306
Marketable debt securities
Schedule of Available-for-sale Securities [Line Items]
Under 1 Year	10,452
1 Year up to 5 Years	112,014
More than 5 Years	7,402
Fair Value	$ 129,868	$ 54,060