Employee Benefit Plans (Schedule Of RSU Activity) (Details) - RSUs [Member] $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Equity Instruments Other than Options, Nonvested [Roll Forward]
Beginning Balance (in shares) | shares	996
RSUs granted (in shares) | shares	618
RSUs vested (in shares) | shares	(412)
RSUs cancelled (in shares) | shares	(72)
Ending Balance (in shares) | shares	1,130
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Beginning Balance (in dollars per share) | $ / shares	$ 36.22
RSUs granted (in dollars per share) | $ / shares	49.45
RSUs vested (in dollars per share) | $ / shares	35.46
RSUs cancelled (in dollars per share) | $ / shares	44.16
Ending Balance (in dollars per share) | $ / shares	$ 43.22
Weighted Average Remaining Contractual Terms	1 year 5 months 6 days
Equity Instruments Other than Options, Nonvested Intrinisc Value | $	$ 66,390