Stock-Based Compensation and Other Employee Benefit Plans (Summary of Stock-Based Compensation Expense and Related Tax Benefits) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Share-based Compensation [Abstract]
Stock-based compensation expense	$ 4,200,000		$ 4,300,000		$ 7,480,000		$ 6,617,000
Income Tax Effects:
Income tax benefit from stock-based compensation	1,800,000		1,800,000		6,600,000		3,300,000
Excess tax benefit from stock-based compensation	$ 100,000	[1]	$ 800,000	[1]	$ 3,386,000	[1]	$ 1,462,000	[1]

[1] Excess tax benefits, which represent cash flows from tax deductions in excess of the recorded tax effect of compensation expense recognized for stock options exercised and vested restricted shares, are classified as financing cash flows in the Company’s condensed unaudited consolidated statements of cash flows.