Securities (Details) (USD $)			1 Months Ended																					9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Jul. 31, 2011 SWS Note receivable	Sep. 30, 2013 U.S. Treasury securities	Dec. 31, 2012 U.S. Treasury securities	Sep. 30, 2013 Bonds	Dec. 31, 2012 Bonds	Sep. 30, 2013 Residential mortgage-backed securities	Dec. 31, 2012 Residential mortgage-backed securities	Sep. 30, 2013 Collateralized mortgage obligations	Dec. 31, 2012 Collateralized mortgage obligations	Sep. 30, 2013 Corporate debt securities	Dec. 31, 2012 Corporate debt securities	Sep. 30, 2013 States and political subdivisions	Dec. 31, 2012 States and political subdivisions	Sep. 30, 2013 Commercial mortgage-backed securities	Dec. 31, 2012 Commercial mortgage-backed securities	Sep. 30, 2013 Equity securities	Dec. 31, 2012 Equity securities	Sep. 30, 2013 Note receivable	Dec. 31, 2012 Note receivable	Sep. 30, 2013 Warrant	Dec. 31, 2012 Warrant	Sep. 30, 2013 Warrant SWS	Sep. 30, 2013 Common Stock SWS
Available for sale
Amortized Cost	$ 1,305,903,000	$ 978,502,000		$ 23,746,000	$ 7,046,000	$ 773,723,000	$ 524,888,000	$ 62,825,000	$ 18,473,000	$ 132,563,000	$ 97,812,000	$ 73,566,000	$ 79,716,000	$ 164,813,000	$ 177,701,000	$ 741,000	$ 1,001,000	$ 19,756,000	$ 19,289,000	$ 42,102,000	$ 40,508,000	$ 12,068,000	$ 12,068,000
Gross Unrealized Gains	21,956,000	15,054,000		86,000	141,000	6,431,000	1,663,000	1,462,000	490,000	720,000	191,000	5,071,000	7,461,000	498,000	196,000	63,000	72,000	1,240,000	1,139,000	6,385,000	3,652,000		49,000
Gross Unrealized Losses	(48,478,000)	(2,603,000)		(17,000)	(2,000)	(37,491,000)	(314,000)	(499,000)	(70,000)	(2,749,000)	(79,000)	(276,000)		(6,493,000)	(2,138,000)							(953,000)
Fair Value	1,279,381,000	990,953,000		23,815,000	7,185,000	742,663,000	526,237,000	63,788,000	18,893,000	130,534,000	97,924,000	78,361,000	87,177,000	158,818,000	175,759,000	804,000	1,073,000	20,996,000	20,428,000	48,487,000	44,160,000	11,115,000	12,117,000
Number of shares included within the available for sale equity securities																									1,475,387
Aggregate Principal amount of senior unsecured loan			$ 50,000,000
Interest rate on senior unsecured loan (as a percent)			8.00%
Period after issuance in which senior unsecured loan may be prepaid			3 years
Maturity term of senior unsecured loan			5 years
Number of shares of common stock available to purchase under warrant																								8,695,652
Warrants exercise price (in dollars per share)																								$ 5.75
Ownership interest percentage the entity would own if warrant was fully exercised																								24.40%