STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Class A	Class B	Common stock Class A	Common stock Class B	Additional paid-in-capital	Accumulated other comprehensive income (loss)	Retained earnings	Retained earnings Class A	Retained earnings Class B	Treasury stock	Deferred compensation
Balance, end of year at Dec. 31, 2013	$ 733,981			$ 1,992	$ 178	$ 16,365	$ (59,099)	$ 1,901,428			$ (1,126,883)
Increase (decrease) in shareholders' equity
Net income	167,505							167,505
Other comprehensive (loss) income	(58,602)						(58,602)
Dividends declared		$ (119,509)	$ (986)						$ (119,509)	$ (986)
Net purchase of treasury stock	(19,255)					(48)					(19,207)
Balance, end of year at Dec. 31, 2014	703,134			1,992	178	16,317	(117,701)	1,948,438			(1,146,090)
Increase (decrease) in shareholders' equity
Net income	174,678							174,678
Other comprehensive (loss) income	20,837						20,837
Dividends declared		(128,082)	(1,058)						(128,082)	(1,058)
Net purchase of treasury stock	(6)					(6)					0
Deferred compensation	0										(9,018)	$ 9,018
Balance, end of year at Dec. 31, 2015	769,503			1,992	178	16,311	(96,864)	1,993,976			(1,155,108)	9,018
Increase (decrease) in shareholders' equity
Net income	210,366							210,366
Other comprehensive (loss) income	(24,517)						(24,517)
Dividends declared		$ (137,297)	$ (1,134)						$ (137,297)	$ (1,134)
Net purchase of treasury stock	(11)					(11)					0
Deferred compensation	0										(738)	738
Balance, end of year at Dec. 31, 2016	$ 816,910			$ 1,992	$ 178	$ 16,300	$ (121,381)	$ 2,065,911			$ (1,155,846)	$ 9,756