Employee Stock-Based Compensation and Benefit Plans (Schedule of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Number of Options
Outstanding at December 31, 2013 (in shares)	3,577,549
Exercised (in shares)	(1,875,339)
Forfeited or expired (in shares)	(390,098)
Outstanding at December 31, 2014 (in shares)	1,312,112	3,577,549
Weighted- Average Exercise Price
Outstanding at December 31, 2013 (in dollars per share)	$ 67.60
Exercised (in dollars per share)	59.87
Forfeited or expired (in dollars per share)	77.36
Outstanding at December 31, 2014 (in dollars per share)	$ 75.72	$ 67.60
Additional Disclosures on Options
Weighted- Average Remaining Contractual Life, Outstanding at December 31, 2013 (in years)	7 months	1 year 3 months 15 days
Aggregate Intrinsic Value, Outstanding at December 31, 2014	$ 5,978
Weighted- Average Remaining Contractual Life, Outstanding at December 31, 2014 (in years)	7 months	1 year 3 months 15 days
Exercisable at December 31, 2014 (in shares)	1,307,487
Weighted Average Exercise Price, Exercisable at December 31, 2014 (in dollars per share)	$ 75.82
Weighted-Average Remaining Contractual Life, Exercisable at December 31, 2014 (in years)	6 months 26 days
Aggregate intrinsic value, options exercisable at December 31, 2014	$ 5,857
Vested or expected to vest
Vested or expected to vest (in shares)	1,311,936
Weighted- Average Exercise Price (in dollars per share)	$ 75.73
Weighted- Average Remaining Contractual Life (in years)	6 months 28 days
Aggregate Intrinsic Value	$ 5,977