Stock Based Compensation - Expense Table (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 1,685,000	$ 1,388,000
Stock Options Compensation Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	185,000	150,000
Nonvested Stock Awards and Restricted Stock Unit Compensation Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	752,000	556,000
Employee Stock Purchase Plan Compensation Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	18,000	17,000
401 (k) Matching Stock Contribution Plan Compensation Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	699,000	649,000
Directors Stock Ownership Plan Compensation Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 31,000	$ 16,000