Share-Based Compensation (Details Textual) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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			$ 1,800,000	$ 3,100,000	$ 2,200,000
Number of shares available for issuance			7,789,532
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			1,713,732
Tax Benefit from Stock Options Exercised			4,500,000	3,900,000	2,200,000
Stock option granted			0	462,229	894,000
Aggregate intrinsic value of stock options exercised			11,400,000	9,900,000	5,600,000
Shares of non-vested common stock granted			211,462
Number of restricted stock units granted			292,478	307,989	0
Estimated weighted average grant date fair value of stock options				$ 5.48	$ 5.21
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			$ 27.78	$ 18.94
Weighted-average period of recognition of unrecognized compensation cost	3 years 172 days
Compensation cost charged against income			3,500,000.0	1,200,000.0
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options			9,200,000
Income tax benefit recognized during the period		468,000	1,400,000.0
Number of restricted stock units granted			292,000	308,000
Shares of non-vested common stock to vest in equal installments		308,000	562,000	308,000	83,000
Nonvested Stock Awards [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			$ 29.77	$ 19.23
Weighted-average period of recognition of unrecognized compensation cost			2 years 274 days
Total unrecognized compensation cost related to stock options			16,600,000
Compensation cost charged against income			8,800,000	11,400,000	9,100,000
Income tax benefit recognized during the period			3,400,000	4,400,000	3,600,000
Shares of non-vested common stock granted			211,000	400,000
Shares of non-vested common stock to vest in equal installments		1,451,000	1,183,000	1,451,000	1,516,000
Employee Stock Option [Member]
Share-Based Compensation (Textual) [Abstract]
Weighted-average period of recognition of unrecognized compensation cost			2 years 73 days
Compensation cost charged against income			1,800,000	1,500,000	1,600,000
Income tax benefit recognized during the period			687,000	603,000	636,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options			$ 3,400,000
Executive Officer [Member]
Share-Based Compensation (Textual) [Abstract]
Minimum vesting period of outstanding options and non vested shares			4 years
Employees - Non-Vested Shares 1 [Member]
Share-Based Compensation (Textual) [Abstract]
Shares of non-vested common stock granted			199,410
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			12,052
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