Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles

The following table provides changes to the opening balances of current assets, total assets, current liabilities and total liabilities resulting from the adoption of the new guidance.

(In thousands)	December 31, 2017		Impact of Adoption		January 1, 2018
Current assets	$	1,879,850	$	3,658	$	1,883,508
Total assets	5,032,985		19,899		5,052,884
Current liabilities	744,102		835		744,937
Total liabilities	4,650,436		7,115		4,657,551

Schedule of Weighted Average Number of Shares

The following is a reconciliation between basic and diluted weighted average shares outstanding:

(In thousands)	Years Ended December 31,
	2018	2017	2016
Basic weighted average shares outstanding	58,066	64,905	71,746
Effect of dilution:
Stock options	15	1	13
Restricted stock units	866	719	651
Diluted weighted average shares outstanding	58,947	65,625	72,410

Schedule of Stock by Class

	Shares Outstanding
(In thousands)	Class A  Common Stock		Class B  Common Stock
Balance at December 31, 2015	60,910		11,484
Share repurchases	(4,120	)	—
Employee and non-employee director stock transactions*	289		—
Balance at December 31, 2016	57,079		11,484
Share repurchases	(7,790	)	—
Employee and non-employee director stock transactions*	312		—
Balance at December 31, 2017	49,601		11,484
Share repurchases	(5,386	)	—
Employee and non-employee director stock transactions*	534		—
Balance at December 31, 2018	44,749		11,484

*Reflects common stock activity in connection with restricted stock units and stock options granted to employees, as well as in connection with the fulfillment of employees' statutory tax withholding obligations for applicable income and other employment taxes and forfeited employee restricted stock units.