Estimated Fair Values Estimated Fair Values (Information on Other Real Estate Owned) (Details) (Fair Value, Measurements, Nonrecurring [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 31, 2011
Covered OREO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current year foreclosures	$ 20,532	$ 40,800
Loan charge-offs recorded due to the measurement and initial recognition of OREO	959	3,787
Write-downs recorded subsequent to forelosure for OREO	122	4,566
Fair value of OREO remeasured in current year	21,344	48,016
Non-covered OREO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current year foreclosures	6,308	6,129
Loan charge-offs recorded due to the measurement and initial recognition of OREO	458	668
Write-downs recorded subsequent to forelosure for OREO	483	749
Fair value of OREO remeasured in current year	$ 8,048	$ 10,705