Share-Based Compensation (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-Based Compensation (Textual) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$ 3,100,000	$ 2,200,000	$ 2,100,000
Number of shares available for issuance	7,753,935
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,220,937
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 19.23	$ 19.99
Tax Benefit from Stock Options Exercised	3,900,000	2,200,000	1,300,000
Stock option granted	462,229	894,000	0
Aggregate intrinsic value of stock options exercised	9,900,000	5,600,000	3,300,000
Shares of non-vested common stock granted	399,900	1,248,000
Number of restricted stock units granted	307,989
Estimated weighted average grant date fair value of stock options	$ 5.48	$ 5.21
Shares of non-vested common stock to vest in equal installments	1,451,000	1,516,000	687,000
Minimum [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	3 years
Expiration period of outstanding options	P5Y
Maximum [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	6 years
Expiration period of outstanding options	P10Y
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation (Textual) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 18.94
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	4 years
Weighted-average period of recognition of unrecognized compensation cost	3 years 256 days
Total unrecognized compensation cost related to stock options	0
Compensation cost charged against income	1,200,000
Income tax benefit recognized during the period	468,000
Nonvested Stock Awards [Member]
Share-Based Compensation (Textual) [Abstract]
Weighted-average period of recognition of unrecognized compensation cost	2 years 329 days
Total unrecognized compensation cost related to stock options	18,500,000
Compensation cost charged against income	11,400,000	9,100,000	6,700,000
Income tax benefit recognized during the period	4,400,000	3,600,000	2,600,000
Employee Stock Option [Member]
Share-Based Compensation (Textual) [Abstract]
Weighted-average period of recognition of unrecognized compensation cost	3 years 37 days
Compensation cost charged against income	1,500,000	1,600,000	2,600,000
Income tax benefit recognized during the period	603,000	636,000	1,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	$ 5,400,000
Employees - Non-Vested Shares 1 [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	3 years
Shares of non-vested common stock granted	385,592
Employees - Non-Vested Shares 1 [Member] | Nonvested Stock Awards [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	4 years
Board of Directors [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	3 years
Shares of non-vested common stock granted	14,308
Board of Directors [Member] | Nonvested Stock Awards [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	3 years
Employees - Non Vested Shares Two Member
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares	4 years
AVC [Member]
Share-Based Compensation (Textual) [Abstract]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years