CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Parent	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Deferred Compensation Employee Stock Trust, Net	Employee Stock Trust	Noncontrolling Interest	Total
Increase (Decrease) in Stockholders' Equity
Adoption of accounting standards	$ 1,393				$ 1,393				$ 1,393
Balance at Dec. 31, 2018	1,949,470	$ 936	$ 1,489,816	$ (8,627)	466,737	$ 825	$ (217)	$ 24,423	1,973,893
Balance (in shares) at Dec. 31, 2018		93,610,000					11,000
Increase (Decrease) in Stockholders' Equity
Net income	38,786				38,786			991	39,777
Other comprehensive loss	7,565			7,565					7,565
Stock-based compensation expense	2,354		2,354						2,354
Common stock issued to board members	140		140						140
Common stock issued to board members (in shares)		8,000
Issuance of common stock related to share-based awards, net	(723)	$ 2	(725)						(723)
Issuance of common stock related to share-based awards, net (in shares)		203,000
Dividends on common stock	(7,464)				(7,464)				(7,464)
Deferred compensation plan	6					2	$ 4		6
Net cash distributed to noncontrolling interest								(1,810)	(1,810)
Balance at Mar. 31, 2019	1,991,527	$ 938	1,491,585	(1,062)	499,452	827	$ (213)	23,604	2,015,131
Balance (in shares) at Mar. 31, 2019		93,821,000					11,000
Increase (Decrease) in Stockholders' Equity
Adoption of accounting standards	(5,691)				(5,691)				(5,691)
Balance at Dec. 31, 2019	2,103,039	$ 906	1,445,233	11,419	644,860	776	$ (155)	25,757	2,128,796
Balance (in shares) at Dec. 31, 2019		90,641,000					8,000
Increase (Decrease) in Stockholders' Equity
Net income	49,636				49,636			3,966	53,602
Other comprehensive loss	9,520			9,520					9,520
Stock-based compensation expense	3,642		3,642						3,642
Common stock issued to board members	146		146						146
Common stock issued to board members (in shares)		10,000
Issuance of common stock related to share-based awards, net	(469)	$ 2	(471)						(469)
Issuance of common stock related to share-based awards, net (in shares)		158,000
Repurchases of common stock	(14,957)	$ (7)	(11,249)		(3,701)				$ (14,957)
Repurchases of common stock (in shares)		(701,000)							(700,901)
Dividends on common stock	(8,158)				(8,158)				$ (8,158)
Deferred compensation plan	3					(2)	$ 5		3
Net cash distributed to noncontrolling interest								(2,701)	(2,701)
Balance at Mar. 31, 2020	$ 2,136,711	$ 901	$ 1,437,301	$ 20,939	$ 676,946	$ 774	$ (150)	$ 27,022	$ 2,163,733
Balance (in shares) at Mar. 31, 2020		90,108,000					8,000