General (Details 10)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) company $ / shares shares	Sep. 30, 2014 USD ($)
Share-based compensation
Stock compensation expense | $	$ 12,897,000	$ 11,961,000	$ 40,593,000	$ 25,983,000
Tax benefit from exercise of stock options and vesting of stock awards - financing cash flow | $			3,887,000	2,805,000
Change to additional paid in capital related to tax net benefits (deficiencies) | $			3,800,000	2,500,000
Excess tax benefits of tax deductions in recognized stock compensation expenses | $			3,900,000	2,800,000
Tax deficiencies and adjustments from exercise of stock options and vesting of stock awards | $			$ (100,000)	$ (300,000)
Minimum
Stock options, Non vested restricted stock awards and nonvested restricted stock units
Estimated forfeitures (as a percent)			0.00%	0.00%
Maximum
Stock options, Non vested restricted stock awards and nonvested restricted stock units
Estimated forfeitures (as a percent)			4.00%	4.00%
Stock options
Stock options, Non vested restricted stock awards and nonvested restricted stock units
Grants in period, weighted average grant date fair value (in dollars per share) | $ / shares			$ 13.91
Expected volatility (as a percent)			25.03%
Stock option activity
Outstanding, beginning of period (in shares)			3,321,063
Granted (in shares)			902,928
Forfeited (in shares)			(140,940)
Exercised (in shares)			(1,062,878)
Outstanding, end of period (in shares)	3,020,173		3,020,173
Vested and expected to vest end of period (in shares)	2,983,943		2,983,943
Exercisable, end of period (in shares)	1,417,576		1,417,576
Weighted average exercise price of stock options
Outstanding, beginning of period (in dollars per share) | $ / shares			$ 50.58
Granted (in dollars per share) | $ / shares			63.61
Forfeited (in dollars per share) | $ / shares			60.21
Exercised (in dollars per share) | $ / shares			47.17
Outstanding, end of period (in dollars per share) | $ / shares	$ 55.23		55.23
Vested and expected to vest end of period (in dollars per share) | $ / shares	55.15		55.15
Exercisable, end of period (in dollars per share) | $ / shares	$ 49.46		$ 49.46
Assumptions used for estimating value of awards granted
Vesting period			3 years
Life of options (Expiration period)			10 years
Restricted stock awards
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares)			1,626,827
Awarded (in shares)			20,115
Vested (in shares)			(94,547)
Outstanding, end of period (in shares)	1,552,395		1,552,395
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share) | $ / shares			$ 57.66
Awarded (in dollars per share) | $ / shares			67.12
Vested (in dollars per share) | $ / shares			57.48
Outstanding, end of period (in dollars per share) | $ / shares	$ 57.79		$ 57.79
Restricted stock awards | Minimum
Assumptions used for estimating value of awards granted
Vesting period			12 months
Restricted stock awards | Maximum
Assumptions used for estimating value of awards granted
Vesting period			42 months
Restricted Stock Units (RSUs)
Assumptions used for estimating value of awards granted
Vesting period			3 years
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares)			156,695
Awarded (in shares)			172,810
Vested (in shares)			(79,036)
Forfeited (in shares)			(21,144)
Outstanding, end of period (in shares)	229,325		229,325
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share) | $ / shares			$ 54.88
Awarded (in dollars per share) | $ / shares			63.95
Vested (in dollars per share) | $ / shares			52.82
Forfeited (in dollars per share) | $ / shares			61.65
Outstanding, end of period (in dollars per share) | $ / shares	$ 61.80		$ 61.80
Performance Based Restricted Stock Units ("PSUs")
Assumptions used for estimating value of awards granted
Expected dividend yield (as a percent)			0.00%
Risk-free interest rate (as a percent)			1.00%
Expected volatility, minimum (as a percent)			15.00%
Expected volatility, maximum (as a percent)			52.00%
Expected volatility, average (as a percent)			28.00%
Vesting period			3 years
Number of trading days considered for average share value			30
Number of companies in peer group | company			54
Nonvested restricted stock awards and units
Awarded (in shares)			43,900
Forfeited (in shares)			(3,906)
Estimated fair value | $			$ 85.00
Performance Based Restricted Stock Units ("PSUs") | Minimum
Assumptions used for estimating value of awards granted
Percentage of shares to be settled			0.00%
Performance Based Restricted Stock Units ("PSUs") | Maximum
Assumptions used for estimating value of awards granted
Percentage of shares to be settled			200.00%