Employee Benefits Stock Based Incentive Plans (Details) (USD $)	12 Months Ended				12 Months Ended									12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 2009 Stock Option and Incentive Plan [Member]	Dec. 31, 2013 2010 Inducement Stock Plan [Member]	Dec. 31, 2012 2010 Inducement Stock Plan [Member]	Dec. 31, 2011 2010 Inducement Stock Plan [Member]	Dec. 31, 2013 Employee Stock Purchase Plans [Member]	Dec. 31, 2013 Qualified Employee Stock Purchase Plan [Member]	Dec. 31, 2013 Non Qualified Employee Stock Purchase Plan [Member]	Dec. 31, 2013 Stock Options [Member] 2009 Stock Option and Incentive Plan [Member]	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2013 Restricted Stock [Member] 2009 Stock Option and Incentive Plan [Member]	Feb. 24, 2014 Performance Shares [Member]	Dec. 31, 2013 Performance Shares [Member]	Feb. 24, 2014 Maximum [Member] Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number												2,074,951	2,264,433		547,680	856,459	985,824
Potential performance shares, incremental expense															$ 4,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				4,000,000	600,000
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period					30,887	7,246	0		156,982	0
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award					The terms of the Inducement Plan are substantially similar to the terms of the 2009 Plan.			Under the ESPPs, eligible employees may purchase common stock of the Company at 85 percent of the lower of the closing price of the Company’s common stock on the first or last day of a six month purchase period on The NASDAQ® Global Select Market. Employees pay for their stock purchases through payroll deductions at a rate equal to any whole percentage from 1 percent to 15 percent of after-tax earnings.			Generally, options expire ten years from the date granted and vest over a three-year graded vesting period for officers and employees and a one-year or less period for non-employee directors.			Stock grants generally vest over a three-year cliff vesting period
Stock or Unit Option Plan Expense	987,000	1,403,000	1,682,000
Restricted Stock or Unit Expense	4,747,000	6,669,000	5,083,000
Allocated Share-based Compensation Expense	5,734,000	8,072,000	6,765,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	2,210,000	3,129,000	2,621,000
Allocated Share-based Compensation Expense, Net of Tax	$ 3,524,000	$ 4,943,000	$ 4,144,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				2,729,136	84,701				208,327	10,508
Potential Incremental Performance Shares Outstanding															438,144