Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified			12 Months Ended			12 Months Ended				3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2013 2000 Employee Option Plan	Dec. 31, 2013 2009 Employee Option Plan	Dec. 31, 2013 2000 Employee Option Plan and 2009 Employee Option Plan	Dec. 31, 2013 2004 Directors Option Plan	Dec. 31, 2013 2012 Directors Restricted Stock Plan	Dec. 31, 2013 Stock Options	Dec. 31, 2012 Stock Options	Dec. 31, 2011 Stock Options	Dec. 31, 2010 Stock Options	Jun. 30, 2013 Restricted Shares	Jun. 30, 2013 Restricted Shares	Dec. 31, 2013 Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award
Number of additional stock options that can be granted (in shares)	0
Shares available for the granting of additional stock options		2,356,150		70,000	95,131
Options ratable vesting period			5 years	3 years
Options exercisable period			10 years	10 years
Number of additional stock options expected to be granted (in shares)				0
Stock option activity
Options outstanding at the beginning of the period (in shares)						13,446,719	14,016,900	12,706,324
Options granted (in shares)						2,788,000	2,990,000	2,551,350
Options exercised (in shares)						(2,636,213)	(3,252,961)	(1,037,674)
Options forfeited (in shares)						(176,280)	(307,220)	(203,100)
Options outstanding at the end of the period (in shares)						13,422,226	13,446,719	14,016,900	12,706,324
Vested and non-vested expected to vest at the end of the period (in shares)						12,159,914
Exercisable at the end of the period (in shares)						5,405,305
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share)						$ 43.39	$ 38.00	$ 33.93
Weighted average exercise price, options granted (in dollars per share)						$ 78.00	$ 53.31	$ 53.45
Weighted average exercise price, options exercised (in dollars per share)						$ 36.46	$ 29.33	$ 25.14
Weighted average exercise price, options forfeited (in dollars per share)						$ 53.65	$ 42.84	$ 39.75
Weighted average exercise price, options outstanding at the end of the period (in dollars per share)						$ 51.80	$ 43.39	$ 38.00	$ 33.93
Weighted average exercise price, vested and non-vested expected to vest (in dollars per share)						$ 51.20
Weighted average exercise price, exercisable (in dollars per share)						$ 41.09
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding						7 years 29 days	7 years 29 days	6 years 10 months 20 days	7 years 2 months 5 days
Weighted average remaining contractual term of options vested and non-vested expected to vest						6 years 11 months 23 days
Weighted average remaining contractual term of options exercisable						5 years 6 months 18 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding (in dollars)						$ 501,706
Aggregate intrinsic value of options, vested and non-vested expected to vest (in dollars)						461,873
Aggregate intrinsic value of options exercisable (in dollars)						259,938
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)						7,951,177
Non-vested options, options granted (in shares)						2,788,000
Non-vested options, options vested (in shares)						(2,545,976)
Non-vested options, options forfeited (in shares)						(176,280)
Non-vested options at the end of the period (in shares)						8,016,921	7,951,177
Weighted Average Fair Value at Grant Date
Weighted average fair value at the grant date, options outstanding at the beginning of the period (in dollars per share)						$ 13.36
Weighted average fair value at grant date, options granted (in dollars per share)						$ 17.42	$ 12.96	$ 14.19
Weighted average fair value at grant date, options vested (in dollars per share)						$ 13.33
Weighted average fair value at grant date, options forfeited (in dollars per share)						$ 13.95
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)						$ 14.77	$ 13.36
Total intrinsic value of stock options exercised (in dollars)						105,756	95,891	29,697
Total fair value of stock options vested (in dollars)						33,932	30,964	28,563
Total compensation cost related to non-vested options not yet recognized (in dollars)						84,230
Weighted average expected amortization period						3 years 4 months 6 days						4 months 20 days
Number of restricted shares issued										12,824	17,045
Weighted-average grant date fair value of restricted shares (in dollars per share)										$ 78.00	$ 53.78
Total compensation cost related to non-vested restricted shares not yet recognized (in dollars)												$ 394