Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended							12 Months Ended			1 Months Ended							12 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended						12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock Options [Member]	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2013 RSUs [Member]	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	Dec. 31, 2012 Employee Stock Purchase Plan [Member]	Dec. 31, 2011 Employee Stock Purchase Plan [Member]	Apr. 30, 2003 2000 Stock Plan [Member]	Apr. 30, 2000 2000 Stock Plan [Member]	Jun. 30, 2012 2006 Long Term Incentive Plan [Member]	Jul. 31, 2010 2006 Long Term Incentive Plan [Member]	Jun. 30, 2008 2006 Long Term Incentive Plan [Member]	Apr. 30, 2006 2006 Long Term Incentive Plan [Member]	Dec. 31, 2013 2006 Long Term Incentive Plan [Member]	Dec. 31, 2013 2006 Long Term Incentive Plan [Member] RSUs [Member]	Apr. 30, 2003 2003 Stock Plan [Member]	Jun. 30, 2013 2003 Stock Plan [Member]	Apr. 30, 2006 Remaining Tranche [Member] 2006 Long Term Incentive Plan [Member]	Apr. 30, 2003 Remaining Tranche [Member] 2003 Stock Plan [Member]	Apr. 30, 2003 Full Vesting Period [Member] 2006 Long Term Incentive Plan [Member]	Apr. 30, 2003 Full Vesting Period [Member] 2003 Stock Plan [Member]	Apr. 30, 2006 First Tranche [Member] 2006 Long Term Incentive Plan [Member]	Apr. 30, 2003 First Tranche [Member] 2003 Stock Plan [Member]	Dec. 31, 2013 Minimum [Member] 2006 Long Term Incentive Plan [Member] RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum Amount Of Stock-Based Compensation Cost Capitalized	$ 500,000	$ 500,000	$ 500,000
Share Based Compensation Arrangement By Share Based Payment Award, Aggregate Option And Employee Stock Purchase Plan, Grants In Period, Weighted Average Grant Date Fair Value	$ 13.29	$ 13.99	$ 14.29
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Intrinsic Value	2,900,000	3,700,000	4,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value				4,200,000	8,100,000	21,800,000
Common Stock, Capital Shares Reserved for Future Issuance												7,350,000				2,500,000			750,000
Additional Authorization Of Shares For Future Issuance													3,000,000	1,500,000	2,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Conversion Ratio																		1.58
Number Of Shares Transferred Under Stock Option Plan											615,290
Stock Option Contractual Life from Grant Date												10 years							10 years
Minimum Percentage Of Exercise Price Granted To Ten Percentage Of Shareholders												110.00%				110.00%			110.00%
Options granted, vesting term (in years)	4 years											4 years									3 years	3 years	4 years	4 years	12 months	12 months	3 years
Percentage Of Expiration Of Stock Options On Resale Restriction																			25.00%
Number of shares reserved for future grant (in shares)								307,500									1,366,297		1,365,290
Number of Shares expired and retired due to plan termination (in shares)																				62,791
Maximum Percentage of compensation contributed by employees (in percentage)								10.00%
Purchase percentage of stock at fair market value (in percentage)								85.00%
Total unrecognized compensation				16,700,000			14,000,000
Weighted-average period of recognition of stock based compensation (in days)	2 years 3 months 29 days	2 years 11 months 26 days
Term Of Stock Appreciation Rights From Date Of Grant																10 years
Period of Measuring the Achievement of Personal Goals																											12 months
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date								15.00%
Non-cash stock-based compensation	17,462,000	14,372,000	13,762,000					420,000	371,000	354,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Total Fair Value				13,000,000	11,100,000	9,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	2,300,000	3,000,000	2,600,000
Maximum Percentage Contribution Of Salary By Employees	100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Defined Contribution Plan Maximum Contribution By Employer Value	6,000
Defined Contribution Plan, Cost Recognized	$ 1,000,000	$ 700,000	$ 0