Impaired Loans and Valuation Allowance for Loan Losses (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	$ 76,378	$ 99,410
Collectively Evaluated for Impairment, Carrying Value	1,147,432	1,116,982
Carrying Value, Total	1,223,810	1,216,392
Individually Evaluated for Impairment, Associated Allowance	6,713	8,192
Collectively Evaluated for Impairment, Associated Allowance	14,827	16,293
Associated Allowance, Total	21,540	24,455
Construction and land development [Member]
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	3,561	5,419
Collectively Evaluated for Impairment, Carrying Value	59,290	48,599
Carrying Value, Total	62,851	54,018
Individually Evaluated for Impairment, Associated Allowance	183	532
Collectively Evaluated for Impairment, Associated Allowance	925	977
Associated Allowance, Total	1,108	1,509
Commercial real estate [Member]
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	33,908	54,812
Collectively Evaluated for Impairment, Carrying Value	444,335	451,748
Carrying Value, Total	478,243	506,560
Individually Evaluated for Impairment, Associated Allowance	1,938	3,468
Collectively Evaluated for Impairment, Associated Allowance	6,510	7,443
Associated Allowance, Total	8,448	10,911
Residential real estate [Member]
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	38,137	38,002
Collectively Evaluated for Impairment, Carrying Value	536,386	512,261
Carrying Value, Total	574,523	550,263
Individually Evaluated for Impairment, Associated Allowance	4,410	4,069
Collectively Evaluated for Impairment, Associated Allowance	6,312	6,757
Associated Allowance, Total	10,722	10,826
Commercial and financial [Member]
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	0	10
Collectively Evaluated for Impairment, Carrying Value	64,752	54,551
Carrying Value, Total	64,752	54,561
Individually Evaluated for Impairment, Associated Allowance	0	0
Collectively Evaluated for Impairment, Associated Allowance	558	417
Associated Allowance, Total	558	417
Consumer [Member]
Loan portfolio and related allowance
Individually Evaluated for Impairment, Carrying Value	772	1,167
Collectively Evaluated for Impairment, Carrying Value	42,669	49,823
Carrying Value, Total	43,441	50,990
Individually Evaluated for Impairment, Associated Allowance	182	123
Collectively Evaluated for Impairment, Associated Allowance	522	669
Associated Allowance, Total	$ 704	$ 792