Investment Securities - Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	$ 7,270	$ 165,688
Less than 12 months, unrealized losses	22	544
More than 12 months, fair value	119	0
More than 12 months, unrealized losses	1	0
Fair Value	7,389	165,688
Accumulated In Investments	23	544
U.S. Treasury and government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	3,621	165,004
Less than 12 months, unrealized losses	5	539
More than 12 months, fair value	39	0
More than 12 months, unrealized losses	0	0
Fair Value	3,660	165,004
Accumulated In Investments	5	539
Municipal Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	2,145
Less than 12 months, unrealized losses	13
More than 12 months, fair value	0
More than 12 months, unrealized losses	0
Fair Value	2,145
Accumulated In Investments	13
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	508	567
Less than 12 months, unrealized losses	3	4
More than 12 months, fair value	80	0
More than 12 months, unrealized losses	1	0
Fair Value	588	567
Accumulated In Investments	4	4
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, fair value	996	117
Less than 12 months, unrealized losses	1	1
More than 12 months, fair value	0	0
More than 12 months, unrealized losses	0	0
Fair Value	996	117
Accumulated In Investments	$ 1	$ 1