Investments (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Securities Pledged As Collateral Amortized Cost	$ 364,300
Payments to Acquire Investments	(375,200)	$ (163,400)
Proceeds from Sale of Available-for-sale Securities	159,548	466,534
Federal Home Loan Bank stock, at cost	17,250		$ 40,609
Net change in FLHB Stock	23,359	24,016
Redemptions of FHLB stock	27,300
Purchases of FHLB Stock	(3,900)
Proceeds From Sale Of Available-For-Sale Securities from Capital Source Inc legacy portfolio		323,600
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities		382,800
Available For Sale Securities Gross Realized Gains from CapitalSource Inc legacy portfolio		0
Federal Home Loan Bank special dividend	1,400
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from Sale of Available-for-sale Securities		797
Available-for-sale Securities, Gross Realized Gains		89
Government agency and government-sponsored enterprise pass through securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from Sale of Available-for-sale Securities	60,300	137,300
Available-for-sale Securities, Gross Realized Gains	2,600	$ 4,800
Texas Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from Sale of Available-for-sale Securities	28,700
Available-for-sale Securities, Gross Realized Gains	698
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from Sale of Available-for-sale Securities	67,500
Available-for-sale Securities, Gross Realized Losses	$ (232)