Stock-Based Compensation (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Stock [Member]
Assumptions used in determining the fair value of the stock-based awards
Risk-free interest rate (as a percent)	0.06%	0.10%	0.06%	0.10%
Volatility, (as a percent)	32.10%	31.80%	32.10%	31.80%
Expected life	6 months	6 months	6 months	6 months
Expected dividend yield (as a percent)	1.70%	0.00%	1.70%	0.00%
Stock Options And Stock Appreciation Rights [Member]
Assumptions used in determining the fair value of the stock-based awards
Risk-free interest rate, minimum (as a percent)	1.20%	0.50%	1.20%	0.50%
Risk-free interest rate, maximum (as a percent)	1.70%	1.00%	1.70%	1.00%
Volatility, minimum (as a percent)	32.80%	33.40%	32.80%	33.40%
Volatility, maximum (as a percent)	34.20%	38.50%	35.10%	38.80%
Expected dividend yield (as a percent)		0.00%		0.00%
Number of Shares
Outstanding at beginning of year (in shares)			5,590
Options and SARs granted (in shares)			683
Options and SARs exercised (in shares)			(555)
Options and SARs canceled (in shares)			(119)
Outstanding at end of period (in shares)	5,599		5,599
Exercisable at end of period (in shares)	2,827		2,827
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share)			$ 15.05
Options and SARs granted (in dollars per share)	$ 29.02		$ 29.02
Options and SARs exercised (in dollars per share)	$ 13.33		$ 13.33
Options and SARs canceled (in dollars per share)	$ 19.75		$ 19.75
Outstanding at end of period (in dollars per share)	$ 16.82		$ 16.82
Exercisable at end of period (in dollars per share)	$ 13.09		$ 13.09
Weighted average remaining contractual life of options and SARs outstanding, at end of period			6 years 9 months 4 days
Weighted average remaining contractual life of options and SARs exercisable, at end of period			4 years 11 months 1 day
Aggregate intrinsic value of options and SARs outstanding	$ 88,246		$ 88,246
Aggregate intrinsic value of options and SARs exercisable	55,067		55,067
Additional disclosure about options and SARs
Closing price of stock (in dollars per share)	$ 32.5		$ 32.5
Weighted average grant date fair value (in dollars per share)	$ 7.44	$ 10.45	$ 7.44	$ 10.45
Total intrinsic value of awards exercised			9,939	26,518
Stock Options And Stock Appreciation Rights [Member] | Minimum [Member]
Assumptions used in determining the fair value of the stock-based awards
Expected life	3 years 8 months 9 days	3 years 11 months 9 days	3 years 8 months 9 days	3 years 11 months 9 days
Expected dividend yield (as a percent)	0.00%		0.00%
Stock Options And Stock Appreciation Rights [Member] | Maximum [Member]
Assumptions used in determining the fair value of the stock-based awards
Expected life	4 years 10 months 6 days	5 years 22 days	4 years 10 months 6 days	5 years 22 days
Expected dividend yield (as a percent)	1.80%		1.80%
Employee Stock Option [Member]
Additional disclosure about options and SARs
Cash received from exercises			$ 2,141	$ 16,212