STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands		Total		Cumulative effect adjustment	[1]	Class A common stock	Class B common stock	Common stock Class A common stock	Common stock Class B common stock	Additional paid-in-capital		Accumulated other comprehensive (loss) income	Retained earnings	Retained earnings Cumulative effect adjustment	[1]	Retained earnings Class A common stock	Retained earnings Class B common stock	Treasury stock	Deferred compensation
Beginning balance at Dec. 31, 2019		$ 1,133,253		$ (1,075)				$ 1,992	$ 178	$ 16,483		$ (116,868)	$ 2,377,558	$ (1,075)				$ (1,158,910)	$ 12,820
Increase (decrease) in shareholders' equity
Accounting standards update		us-gaap:AccountingStandardsUpdate201613Member
Net income		$ 59,326											59,326
Other comprehensive loss		(29,576)										(29,576)
Dividends declared:						$ (44,572)	$ (368)									$ (44,572)	$ (368)
Net purchase of treasury stock		4	[2]							4	[2]							0
Deferred compensation		0																(772)	772
Ending balance at Mar. 31, 2020		1,116,992						1,992	178	16,487		(146,444)	2,390,869					(1,159,682)	13,592
Beginning balance at Dec. 31, 2020		1,188,048						1,992	178	16,487		(78,143)	2,393,624					(1,163,670)	17,580
Increase (decrease) in shareholders' equity
Net income		73,566											73,566
Other comprehensive loss		(5,289)										(5,289)
Dividends declared:						$ (47,806)	$ (395)									$ (47,806)	$ (395)
Net purchase of treasury stock		9	[2]							9	[2]							0
Deferred compensation		0																(846)	846
Rabbi trust distribution	[3]	0																876	(876)
Ending balance at Mar. 31, 2021		$ 1,208,133						$ 1,992	$ 178	$ 16,496		$ (83,432)	$ 2,418,989					$ (1,163,640)	$ 17,550

[1] The cumulative effect adjustment is related to the implementation of credit loss allowance accounting guidance effective January 1, 2020.

[2] Net purchases of treasury stock in 2021 and 2020 include the repurchase of our Class A common stock in the open market that were subsequently distributed to satisfy stock based compensation awards.

[3] Distributions of our Class A shares were made from the rabbi trust to a retired director in 2021.