Fair Value Measurements Fair Value Measurement, Measured On Non-Recurring Basis, Signfiicant Unobservable Inputs, Quantitative Information (Details) - Fair Value, Measurements, Nonrecurring [Member] - Impaired Loans [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Carrying Value		$ 32,836	$ 0
Fair Value Measurements, Valuation Techniques		Discounted cash flows
Fair Value Measurements, Significant Unobservable Input		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]	55.00%
Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum	[1]	73.00%
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average	[1]	60.00%

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