Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Non-Cash Stock-Based Compensation Expense and Related Tax Effects) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Non-cash stock-based compensation expense				$ 10,551	$ 11,291
Income Tax Effects:
Income tax effect of non-cash stock-based compensation		$ 1,300	$ 1,700	3,800	5,600
Excess tax benefit from non-cash stock-based compensation	[1]	0	300	100	1,400
Net income tax effect		43,378	38,816	126,170	54,331
ASU 2016-09 [Member]
Income Tax Effects:
Net income tax effect				100
General and Administrative Expenses [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Non-cash stock-based compensation expense		$ 3,400	$ 3,900	$ 10,500	$ 11,300

[1] Excess tax benefits represent cash flows from tax deductions in excess of the tax effect of compensation expense associated with share-based payment arrangements. For the nine month period ended September 30, 2017, the Company incurred a net tax deficiency of $0.1 million related to the vesting of share-based payment awards and excess tax benefits were de minimis. As discussed in Note 1 - Business, Basis of Presentation and Significant Accounting Policies, the Company adopted ASU 2016-09 effective January 1, 2017 on a prospective basis. ASU 2016-09 changed the required presentation of excess tax benefits in the consolidated statement of cash flows from financing activities to operating activities. Excess tax benefits for the comparative prior year period are classified as cash flows from financing activities.