Senior Notes (Narrative) (Details) (Senior Notes [Member], USD $)	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Face Value	$ 705,000,000		$ 405,000,000
Balance sheet leverage ratio	0.76
Maximum [Member]
Debt Instrument [Line Items]
Balance sheet leverage ratio	1.50
5.875% Senior Notes Dues April 2024 [Member]
Debt Instrument [Line Items]
Face Value	$ 300,000,000	$ 300,000,000	$ 0
Interest Rate	5.875%	5.875%
Public offering price percentage of principal amount		99.068%