Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total	Common Stock	Additional Paid-In Capital	(Distributions in Excess of Earnings/Earnings in Excess of Distributions	(Distributions in Excess of Earnings/Earnings in Excess of Distributions Cumulative Effect, Period of Adoption, Adjustment	[3]	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	[3]	Treasury Stock	Noncontrolling Interest
Balance, January 1, 2018 at Dec. 31, 2017		$ 1,198,919	$ 1,240	$ 1,190,906	$ 31,541			$ (24,446)				$ (322)
Beginning Balance (in shares) at Dec. 31, 2017			124,008
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised		1,887	$ 1	1,886
Proceeds from stock options exercised (in shares)			103
Stock based compensation expense		22,049		22,049
Shares withheld for net settlements of share-based awards	[1]	(3,820)	$ (2)	(3,818)
Shares withheld for net settlements of share-based awards (in shares)	[1]		(173)
Restricted stock granted			$ 9	(9)
Restricted stock granted (in shares)			906
Restricted stock canceled (in shares)			(73)
Dividends - paid		(229,498)			(229,498)
Other adjustments to Additional Paid-In-Capital	[2]	(632)		(632)
Purchase of treasury shares		(95,175)									$ (95,175)
Purchase of treasury shares (in shares)			(4,210)								4,210
Issuance of common stock (ESPP)		534		534
Issuance of common stock (ESPP) (in shares)			24
Net Income		144,827			145,089							(262)
Other comprehensive income		813						828				(15)
Balance, December 31, 2018 at Dec. 31, 2018		1,039,904	$ 1,248	1,210,916	(52,868)	$ (968)		(23,618)	$ 968		$ (95,175)	(599)
Ending Balance (in shares) at Dec. 31, 2018			120,585								4,210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised		1,258		1,258
Proceeds from stock options exercised (in shares)			78
Stock based compensation expense		22,344		22,344
Shares withheld for net settlements of share-based awards	[1]	(4,179)	$ (2)	(4,177)
Shares withheld for net settlements of share-based awards (in shares)	[1]		(198)
Restricted stock granted			$ 8	(8)
Restricted stock granted (in shares)			788
Restricted stock canceled (in shares)			(58)
Dividends - paid		(232,546)			(232,546)
Issuance of common stock (ESPP)		532		532
Issuance of common stock (ESPP) (in shares)			30
Net Income		166,412			166,603							(191)
Other comprehensive income		3,291						2,315				8
Balance, December 31, 2018 at Dec. 31, 2019		$ 996,048	$ 1,254	1,230,865	(119,779)			(20,335)			$ (95,175)	(782)
Ending Balance (in shares) at Dec. 31, 2019			121,225								4,210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201802Member
Other comprehensive income (loss)		$ 2,323
Stock based compensation expense		23,896		23,896
Shares withheld for net settlements of share-based awards	[1]	(2,789)	$ (1)	(2,788)
Shares withheld for net settlements of share-based awards (in shares)	[1]		(174)
Restricted stock granted			$ 9	(9)
Restricted stock granted (in shares)			900
Restricted stock canceled (in shares)			(58)
Dividends - paid		(216,145)			(216,145)
Other adjustments to Additional Paid-In-Capital	[4]	9,687		9,687
Purchase of treasury shares		(9,771)									$ (9,771)
Purchase of treasury shares (in shares)			(625)								625
Issuance of common stock (ESPP)		616		616
Issuance of common stock (ESPP) (in shares)			50
Net Income		112,831			113,032							(201)
Other comprehensive income		(2,291)						(2,254)				(37)
Balance, December 31, 2018 at Dec. 31, 2020		$ 912,082	$ 1,262	$ 1,262,267	$ (222,892)			$ (22,589)			$ (104,946)	$ (1,020)
Ending Balance (in shares) at Dec. 31, 2020			121,318								4,835

[1] During the years ended December 31, 2020, 2019 and 2018, the Company withheld shares through net share settlements to satisfy statutory tax withholding requirements upon vesting of shares of restricted stock held by employees.

[2] Represents a cumulative-effect adjustment upon adoption of ASU No. 2016-16, "Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory." Refer to Note 1 - Summary of Business Organization, Operations and Significant Accounting Policies - Recent Accounting Pronouncements for further information.

[3] On January 1, 2019, the Company adopted Accounting Standard Update ("ASU") No. 2018-02 "Income Statement-Reporting Comprehensive Income-Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income". Refer to Note 1 - Summary of Business Organization, Operations and Significant Accounting Policies - Recent Accounting Pronouncements for further information.

[4] ON February 26, 2020 (the “Effective Date”), the Company and its Chief Executive Officer (“CEO”) entered into an amended and restated executive retirement agreement that amends the CEO’s executive retirement agreement. The amended and restated executive retirement agreement provides that upon the CEO’s retirement from the Company, the Company will pay a lump sum equal to $8,925,065 (the “Grandfathered Payment”) which will be paid in the form of a fixed number of shares of the Company’s common stock The fair value of the Grandfathered Payment was reclassified to stockholders’ equity. Additional shares of the Company’s common stock are credited with a value equal to any dividends declared and paid on the Company’s shares of common stock. Refer to Note 14 – Benefit Plans for further information.