Benefit Plans Benefit Plans - Defined Contribution Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Cost Recognized	$ 7,667	$ 8,357	$ 6,483
Employee Contributions First Six Percent [Member] | Prior to July 1, 2003 Hire Date [Member]
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Participant Contribution Percentage	6.00%
Effective January 1, 2011 to December 31, 2011 [Member] | Employee Contributions First Six Percent [Member] | Prior to July 1, 2003 Hire Date [Member]
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	25.00%
Effective January 1, 2011 to December 31, 2011 [Member] | Employee Contributions First Six Percent [Member] | Subsequent to July 1, 2003 Hire Date [Member]
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	55.00%
Effective January 1, 2012 to December 31, 2012 [Domain] | Employee Contributions First Six Percent [Member] | Prior to July 1, 2003 Hire Date [Member]
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	30.00%
Effective January 1, 2012 to December 31, 2012 [Domain] | Employee Contributions First Six Percent [Member] | Subsequent to July 1, 2003 Hire Date [Member]
Defined Contribution Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	60.00%