Acquisitions (Summary Of Transaction And Acquisition-Related Costs) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Acquisitions [Abstract]
Transaction costs	[1],[2]			$ 15,981
Severance costs	[1],[2]			31,734
Stay bonuses	[1],[2]			14,804
Acceleration of Alterra long-term incentive compensation awards and restricted stock awards	[1],[2]			12,621
Total transaction and acquisition-related costs	[1]	$ 0	$ 0	$ 75,140	[2]

[1] In connection with the acquisition of Alterra, the Company incurred transaction costs of $16.0 million for the year ended December 31, 2013, which primarily consist of due diligence, legal and investment banking costs. Additionally, the Company incurred severance costs of $31.7 million, stay bonuses of $14.8 million and other compensation costs totaling $12.6 million related to the acceleration of certain long-term incentive compensation awards and restricted stock awards that were granted by Alterra prior to the acquisition.

[2] In connection with the acquisition of Alterra, the Company incurred transaction costs of $16.0 million for the year ended December 31, 2013, which primarily consist of due diligence, legal and investment banking costs. Additionally, the Company incurred severance costs of $31.7 million, stay bonuses of $14.8 million and other compensation costs totaling $12.6 million related to the acceleration of certain long-term incentive compensation awards and restricted stock awards that were granted by Alterra prior to the acquisition.