Stock-Based Compensation (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended			72 Months Ended	12 Months Ended							12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2012 Stock Options Plans [Member]	Dec. 31, 2011 Stock Options Plans [Member]	Dec. 31, 2010 Stock Options Plans [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member]	May 16, 2007 2012 Long-term Incentive Plan [Member] Maximum [Member]	Dec. 31, 2012 2007 Incentive Plan [Member]	May 09, 2012 2007 Incentive Plan [Member]	Dec. 31, 2012 2007 Incentive Plan [Member] Maximum [Member] Stock Options Plans [Member]	Dec. 31, 2012 2007 Incentive Plan [Member] Maximum [Member] Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 2007 Incentive Plan [Member] Minimum [Member] Stock Options Plans [Member]	Dec. 31, 2012 2007 Incentive Plan [Member] Minimum [Member] Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Treasury Stock [Member]	Dec. 31, 2011 Treasury Stock [Member]	Dec. 31, 2010 Treasury Stock [Member]
Share Based Compensation Arrangement by Share Based Payment Award [Line Items]
Number of common stock reserved for issuance											3,200,000		3,200,000
Expiration year												Dec. 31, 2007
Vesting period (years)														5 years	5 years	3 years	3 years
Option awards contractual term (years)												10 years
Weighted average remaining life	3 years 10 months 24 days				1 year 4 months 24 days
Common stock to non-employee directors																		2,000	3,000	4,000
Stock repurchase program authorized share amount	15,000,000			15,000,000
Common stock repurchased, shares			6,000	11,518,000
Common stock repurchased price per share			$ 56.94
Common stock repurchased, value				$ 335,110
Weighted-average grant-date fair value of options granted	$ 28.71	$ 25.39	$ 19.10
Total intrinsic value of options exercised	4,226	1,148	1,714
Recognized stock-based compensation costs					2,176	1,885	2,436	11,887	8,186	4,262
Recognized stock-based compensation costs, net of tax					1,378	1,194	1,543	7,530	5,186	2,700
Pre-tax unrecognized compensation expense	$ 15,437			$ 15,437	$ 2,096
Recognized expense over a weighted-average period, years	2 years 10 months 24 days