Capital Stock (Details) - USD ($) $ in Thousands		6 Months Ended
	Apr. 03, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Class of Stock [Line Items]
Payments for Repurchase of Common Stock		$ 15,264	$ 8,764
Class A Common Stock
Class of Stock [Line Items]
Common Stock, Shares, Outstanding		21,720,287		21,928,932
Stock Repurchased and Retired During Period, Shares		565,875	325,418
Payments for Repurchase of Common Stock		$ 14,674	$ 8,143
Stock Repurchase Program, Remaining Authorized Repurchase Amount		434,125
Class A Common Stock | 2015 Equity Compensation Plan
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	2,000,000
Class B Common Stock
Class of Stock [Line Items]
Common Stock, Shares, Outstanding		23,786,296		23,859,483