Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 30, 2006
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
Equity Instruments Other than Options, Vested in Period, Total Intrinsic Value	$ 8,900,000	9,000,000	2,900,000
Options granted, vesting term (in years)	4 years
Non-cash stock-based compensation	$ 16,825,000	20,014,000	17,462,000
Equity Instruments Other than Options, Vested in Period, Fair Value	$ 8,800,000	8,400,000	2,300,000
Maximum Percentage Contribution Of Salary By Employees	100.00%
Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Maximum Contribution By Employer Value	$ 6,000
Cost Recognized	$ 900,000	$ 1,000,000	$ 1,000,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants In Period, Weighted Average Grant Date Fair Value	$ 10.83	$ 12.04	$ 13.29
Options, Exercises in Period, Intrinsic Value	$ 11,400,000	$ 3,400,000	$ 4,200,000
Total unrecognized compensation	$ 6,400,000
Weighted-average period of recognition of stock based compensation (in days)	2 years 4 months 24 days
Options, Vested in Period, Total Fair Value	$ 6,500,000	$ 10,000,000	13,000,000
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation	$ 19,600,000
Weighted-average period of recognition of stock based compensation (in days)	2 years 6 months
2006 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance				2,500,000
Number of Additional Shares Authorized	8,500,000
Equity Instruments Other Than Options, Conversion Ratio	1.58
Minimum Percentage Of Exercise Price Granted To Ten Percentage Of Shareholders	110.00%
Options granted, vesting term (in years)		4 years
Number of shares reserved for future grant (in shares)	1,500,000
Term Of Stock Appreciation Rights From Date Of Grant	10 years
2006 Long Term Incentive Plan [Member] | First Tranche [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting term (in years)	12 months
2006 Long Term Incentive Plan [Member] | Remaining Tranche [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting term (in years)	3 years
2006 Long Term Incentive Plan [Member] | Minimum [Member] | RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting term (in years)	3 years
Period of Measuring the Achievement of Personal Goals	12 months
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for future grant (in shares)	100,000
Maximum Percentage of compensation contributed by employees (in percentage)	10.00%
Purchase percentage of stock at fair market value (in percentage)	85.00%
discount from Market Price, Purchase Date	15.00%
Non-cash stock-based compensation	$ 539,000	$ 523,000	$ 420,000