Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Quarterly Financial Information (Unaudited) [Abstract]
Interest Income	$ 67,562	$ 66,918	$ 66,392	$ 63,951	$ 60,730	$ 63,410	$ 64,475	$ 52,452	$ 264,823	[1]	$ 241,067	[2]	$ 246,729	[2]
Total interest expense	36,591	34,735	34,528	33,162	44,606	48,886	42,502	34,726	139,016	[3]	170,720	[4]	137,276	[4]
Net interest income	30,971	32,183	31,864	30,789	16,124	14,524	21,973	17,726	125,807		70,347		109,453
(Provision for)/release of allowance for loan losses	(3,366)	1,164	(110)	(76)	462	(511)	1,583	(573)	(2,388)		961		481
Interest Income (Expense), after Provision for Loan Loss	27,605	33,347	31,754	30,713	16,586	14,013	23,556	17,153	123,419		71,308		109,934
Guarantee and commitment fees	3,780	3,532	3,388	3,377	3,563	3,644	3,703	3,784	14,077		14,694		15,627
Gain (loss) on derivatives instruments and hedging activity net pretax	1,592	(9,568)	14,389	(3,882)	(9,178)	808	(5,698)	(7,578)
Gains/(losses) on trading securities	696	(8)	170	362	13,857	16,369	7,748	655	1,220		38,629		(819)
Gains/(losses) on sale of available-for-sale investment securities	0	3	0	6	0	(396)	143	15	9		(238)		2,113
(Losses)/gains on sale of real estate owned	0	0	0	(1)	(28)	0	168	(3)	(1)		137		1,236
Other income	372	1,060	260	613	920	502	200	92	2,305		1,714		3,057
Non-interest income	6,440	(4,981)	18,207	475	9,134	20,927	6,264	(3,035)	20,141		33,290		54,440
Noninterest Expense	5,865	10,421	10,853	8,343	8,594	7,095	7,856	7,947	35,482	[5]	31,492	[6]	33,107	[6]
Income before income taxes	28,180	17,945	39,108	22,845	17,126	27,845	21,964	6,171	108,078		73,106		131,267
Income tax expense	9,912	6,327	13,769	4,231	2,769	7,564	(6,368)	(1,141)	34,239		2,824		33,752
Net income	18,268	11,618	25,339	18,614	14,357	20,281	28,332	7,312	73,839		70,282		97,515
Less: Net income attributable to non-controlling interest	60	36	119	(5,354)	(5,414)	(5,412)	(5,819)	(5,547)	(5,139)		(22,192)		(22,187)
Net Income (Loss) Attributable to Parent	18,328	11,654	25,458	13,260	8,943	14,869	22,513	1,765	68,700		48,090		75,328
Preferred Stock Dividends, Income Statement Impact	(3,296)	(3,295)	(3,296)	(3,295)	(3,296)	(3,283)	(2,308)	(952)	(13,182)		(9,839)		(3,495)
Loss on retirement of preferred stock	0	0	0	(8,147)					(8,147)		0		0
Net Income (Loss) Available to Common Stockholders, Basic	$ 15,032	$ 8,359	$ 22,162	$ 1,818	$ 5,647	$ 11,586	$ 20,205	$ 813	$ 47,371		$ 38,251		$ 71,833
Basic earnings per common share	$ 1.39	$ 0.76	$ 2.01	$ 0.17	$ 0.52	$ 1.06	$ 1.85	$ 0.07	$ 4.33		$ 3.50		$ 6.64
Diluted earnings per common share	$ 1.35	$ 0.74	$ 1.94	$ 0.16	$ 0.50	$ 1.02	$ 1.78	$ 0.07	$ 4.19000		$ 3.37000		$ 6.41000

[1] Includes reconciling adjustments for the amortization of premiums and discounts on assets consolidated at fair value to reflect core earnings amounts.

[2] Includes reconciling adjustments for the amortization of premiums and discounts on assets consolidated at fair value to reflect core earnings amounts and interest income related to securities purchased under agreements to resell.

[3] Based on effective funding cost determined for each operating segment, including expenses related to interest rate swaps not designated as hedges, which are included in "Gains/(losses) on financial derivatives and hedging activities" on the consolidated financial statements.

[4] Based on effective funding cost determined for each operating segment, including expenses related to interest rate swaps not designated as hedges, which are included in "Gains/(losses) on financial derivatives and hedging activities" on the consolidated financial statements. Includes reconciling adjustments for interest expense related to securities sold, not yet purchased.

[5] Includes directly attributable costs and an allocation of indirectly attributable costs based on headcount

[6] Includes directly attributable costs and an allocation of indirectly attributable costs based on headcount.