Loans And Allowance For Loan Losses (Southwest's Loan Classifications) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Jun. 19, 2009
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	$ 1,305,069	$ 1,254,476
Less: Allowance for loan losses	(34,918)	(36,607)
Total loans, net, Noncovered	1,270,151	1,217,869
Loans receivable, Covered	15,053	16,427
Less: Allowance for loan losses	(7)	(56)	(35,000)
Net covered loans receivable	15,046	16,371
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	265,394	254,087
Loans receivable, Covered	917	971
Commercial Real Estate [Member] | Real Estate Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	755,680	740,997
Loans receivable, Covered	10,498	11,282
Commercial Real Estate [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	165,820	143,650
Loans receivable, Covered	187	198
One-To-Four Family Residential [Member] | Real Estate Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	81,199	80,058
Loans receivable, Covered	3,420	3,930
One-To-Four Family Residential [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	6,629	4,646
Guaranteed Student Loans [Member] | Installment And Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	4,318	4,394
Other [Member] | Installment And Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Noncovered	26,029	26,644
Loans receivable, Covered	$ 31	$ 46