Employee Benefit Plans (Summary Of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares
Beginning Balance Outstanding (in shares)	2,478,000
Granted (in shares)	0	632,000	825,000
Exercised (in shares)	(54,000)
Forfeited (in shares)	(205,000)
Ending Balance Outstanding (in shares)	2,219,000	2,478,000
Vested and expected to vest (in shares)	2,187,000
Exercisable (in shares)	(1,849,000)
Weighted average exercise price
Balance Outstanding (in dollars per share)	$ 46.50	$ 47.24
Granted (in dollars per share)	0.00
Exercised (in dollars per share)	26.10
Forfeited (in dollars per share)	60.70
Vested and expected to vest (in dollars per share)	46.30
Exercisable (in dollars per share)	$ 43.74
Remaining contractual term (years)
Outstanding	5 years 1 month 10 days	7 years 2 months 19 days
Vested and expected to vest	5 years 29 days
Exercisable	4 years 7 months 10 days
Aggregate intrinsic value
Outstanding	$ 4,321	$ 42,324
Vested and expected to vest	4,323
Exercisable	$ 4,323