General - Stock Compensation (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) company $ / shares shares	Mar. 31, 2015 USD ($)
Share-based compensation
Stock compensation expense | $	$ 8,887,000	$ 13,901,000
Tax benefit from exercise of stock options and vesting of stock awards | $	383,000	2,961,000
Change to additional paid in capital related to tax net benefits (deficiencies) | $	300,000	2,900,000
Excess tax benefits of tax deductions in recognized stock compensation expenses | $	400,000	3,000,000
Tax deficiencies and adjustments from exercise of stock options and vesting of stock awards | $	$ (100,000)	$ (100,000)
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)	$ 14.97
Expected volatility (as a percent)	27.75%
Stock option activity
Outstanding, beginning of period (in shares) | shares	2,939,840
Granted (in shares) | shares	424,060
Forfeited (in shares) | shares	(13,426)
Exercised (in shares) | shares	(157,974)
Outstanding, end of period (in shares) | shares	3,192,500
Vested and expected to vest end of period (in shares) | shares	3,153,163
Exercisable, end of period (in shares) | shares	1,823,039
Weighted average exercise price of stock options
Outstanding, beginning of period (in dollars per share)	$ 55.13
Granted (in dollars per share)	63.82
Forfeited (in dollars per share)	59.12
Exercised (in dollars per share)	48.30
Outstanding, end of period (in dollars per share)	56.60
Vested and expected to vest end of period (in dollars per share)	56.54
Exercisable, end of period (in dollars per share)	$ 52.84
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) | shares	1,109,622
Outstanding, end of period (in shares) | shares	1,109,622
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share)	$ 57.88
Outstanding, end of period (in dollars per share)	$ 57.88
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)
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares) | shares	231,088
Awarded (in shares) | shares	51,521
Vested (in shares) | shares	(51,356)
Forfeited (in shares) | shares	(6,552)
Outstanding, end of period (in shares) | shares	224,701
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share)	$ 61.53
Awarded (in dollars per share)	64.87
Vested (in dollars per share)	63.78
Forfeited (in dollars per share)	63.63
Outstanding, end of period (in dollars per share)	$ 61.72
Assumptions used for estimating value of awards granted
Vesting period	3 years
Performance Based Restricted Stock Units ("PSUs")
Nonvested restricted stock awards and units
Outstanding, beginning of period (in shares) | shares	36,938
Awarded (in shares) | shares	65,067
Outstanding, end of period (in shares) | shares	102,005
Estimated fair value | $	$ 97.60
Weighted average exercise price of nonvested restricted stock award and units
Outstanding, beginning of period (in dollars per share)	$ 85.00
Awarded (in dollars per share)	97.60
Outstanding, end of period (in dollars per share)	$ 93.04
Assumptions used for estimating value of awards granted
Vesting period	3 years
Expected dividend yield (as a percent)	0.00%
Risk-free interest rate (as a percent)	1.00%
Expected volatility, minimum (as a percent)	16.00%
Expected volatility, maximum (as a percent)	81.00%
Expected volatility, average (as a percent)	32.00%
Number of trading days considered for average share value	30
Number of companies in peer group | company	56
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%