Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Cost Recognized	$ 5,000,000	$ 3,800,000	$ 3,000,000
Other Deferred Compensation Arrangements, Liability, Current and Noncurrent	5,600,000	1,900,000
Salary continuation plan minimum period	10 years
Salary continuation plan maximum period	20 years
Present Value Of Future Salary Contribution Plan Benefits	42,900,000	19,000,000
Postemployment Benefits, Period Expense	2,900,000	849,000	2,500,000
Deferred Compensation Cash-based Arrangements, Liability, Current and Noncurrent	5,600,000	3,900,000
Cash Surrender Value of Life Insurance	294,300,000	96,900,000
Other Postretirement Defined Benefit Plan, Liabilities	6,200,000	1,800,000
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Contributions by Employer	140,000	123,000	116,000
Other Deferred Compensation Arrangements, Liability, Current and Noncurrent	812,000	678,000
Percentage Of Deferred Salary	50.00%
Pension and Other Postretirement Defined Benefit Plans, Liabilities	$ 3,900,000	$ 2,100,000