Employee Benefit Plans (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) shares
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock options available to be awarded (in shares)	541,000
Anticipated contribution to benefit plan | $	$ 1.6
Employee Stock Option
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Incentive stock options and SARs exercisable period	10 years
Performance Shares
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Award vesting rights percentage	33.33%
Median return on average assets of all FDIC insured depository institutions time period	20 years
Maximum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock issued upon the exercise of stock options, SARs and stock awards (in shares)	750,000