Fair Value Measurements Fair Value Measurement, Measured On Non-Recurring Basis, Signfiicant Unobservable Inputs, Quantitative Information (Details) - Fair Value, Measurements, Nonrecurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2017		Jun. 30, 2016
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Carrying Value		$ 3,570		$ 42,342
Fair Value Measurements, Valuation Techniques		Discounted cash flows		Discounted cash flows
Fair Value Measurements, Significant Unobservable Input		Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs		Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract]
Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Minimum	[1]	75.00%		25.00%
Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum	[1]	90.00%		71.00%
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average	[1]	83.00%		58.00%
Real estate and other repossessed assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Carrying Value		$ 530		$ 1,693
Fair Value Measurements, Valuation Techniques		Appraised value, as adjusted		Appraised value, as adjusted
Fair Value Measurements, Significant Unobservable Input		Marketability adjustment off appraised value2	[2]	Marketability adjustments off appraised value2	[3]
Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract]
Fair Value Measurement, Percentage of Appraised Value. Minimum		65.00%		68.00%
Fair Value Measurement, Percentage of Appraised Value, Maximum		88.00%		80.00%
Fair Value Measurement, Percentage of Appraised Value, Weighted Average		80.00%		71.00%

[1] Represents fair value as a percentage of the unpaid principal balance.

[2] Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value.

[3] 2 Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value.