Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Treasury Stock, Common	Total
Beginning balance at Dec. 31, 2020	$ 1,600	$ 3,424,624	$ (5,006)	$ (2,401,988)	$ (83,673)	$ 935,557
Stockholders' Equity, Beginning balance (in shares) at Dec. 31, 2020	160,014,960
Treasury stock, common shares, Beginning balance (in shares) at Dec. 31, 2020					(7,052,769)
Increase (Decrease) in Stockholders' Equity
Treasury stock purchased					$ (1,746)	(1,746)
Treasury stock purchased (in shares)					(184,776)
Cash dividends				(44,486)		(44,486)
Shares issued under ESPP		371				371
Shares issued under ESPP (in shares)	44,116
Stock-based compensation, net of forfeitures	$ 9	5,832				5,841
Stock-based compensation, net of forfeitures (in shares)	923,330				(40,904)
Net proceeds from issuance of common stock	$ 4	3,397				3,401
Net proceeds from issuance of common stock (in shares)	357,148
Comprehensive income (loss)
Net income				12,921		12,921
Interest rate swap gain, net of reclassifications to earnings			1,962			1,962
Ending balance at Jun. 30, 2021	$ 1,613	3,434,224	(3,044)	(2,433,553)	$ (85,419)	913,821
Stockholders' Equity, Ending balance (in shares) at Jun. 30, 2021	161,339,554
Treasury stock, common shares, Ending balance (in shares) at Jun. 30, 2021					(7,278,449)
Beginning balance at Mar. 31, 2021	$ 1,613	3,430,910	(4,010)	(2,419,974)	$ (85,415)	923,124
Stockholders' Equity, Beginning balance (in shares) at Mar. 31, 2021	161,323,492
Treasury stock, common shares, Beginning balance (in shares) at Mar. 31, 2021					(7,263,173)
Increase (Decrease) in Stockholders' Equity
Treasury stock purchased					$ (4)	(4)
Treasury stock purchased (in shares)					(383)
Cash dividends				(22,331)		(22,331)
Shares issued under ESPP		136				136
Shares issued under ESPP (in shares)	16,062
Stock-based compensation, net of forfeitures		3,178				3,178
Stock-based compensation, net of forfeitures (in shares)					(14,893)
Comprehensive income (loss)
Net income				8,752		8,752
Interest rate swap gain, net of reclassifications to earnings			966			966
Ending balance at Jun. 30, 2021	$ 1,613	3,434,224	(3,044)	(2,433,553)	$ (85,419)	913,821
Stockholders' Equity, Ending balance (in shares) at Jun. 30, 2021	161,339,554
Treasury stock, common shares, Ending balance (in shares) at Jun. 30, 2021					(7,278,449)
Beginning balance at Dec. 31, 2021	$ 1,615	3,440,059	(984)	(2,463,114)	$ (86,138)	$ 891,438
Stockholders' Equity, Beginning balance (in shares) at Dec. 31, 2021	161,482,852
Treasury stock, common shares, Beginning balance (in shares) at Dec. 31, 2021					(7,417,401)	7,417,401
Increase (Decrease) in Stockholders' Equity
Treasury stock purchased					$ (2,366)	$ (2,366)
Treasury stock purchased (in shares)					(272,706)
Cash dividends				(45,167)		(45,167)
Shares issued under ESPP		295				295
Shares issued under ESPP (in shares)	38,846
Stock-based compensation, net of forfeitures	$ 14	6,023				6,037
Stock-based compensation, net of forfeitures (in shares)	1,416,672				(50,812)
Net proceeds from issuance of common stock	$ 4	4,226				4,230
Net proceeds from issuance of common stock (in shares)	447,020
Comprehensive income (loss)
Net income				18,467		18,467
Interest rate swap gain, net of reclassifications to earnings			574			574
Amortization of dedesignated interest rate swap			$ 410			410
Ending balance at Jun. 30, 2022	$ 1,633	3,450,603		(2,489,814)	$ (88,504)	$ 873,918
Stockholders' Equity, Ending balance (in shares) at Jun. 30, 2022	163,385,390
Treasury stock, common shares, Ending balance (in shares) at Jun. 30, 2022					(7,740,919)	7,740,919
Beginning balance at Mar. 31, 2022	$ 1,629	3,443,261		(2,484,066)	$ (88,501)	$ 872,323
Stockholders' Equity, Beginning balance (in shares) at Mar. 31, 2022	162,919,584
Treasury stock, common shares, Beginning balance (in shares) at Mar. 31, 2022					(7,698,812)
Increase (Decrease) in Stockholders' Equity
Treasury stock purchased					$ (3)	(3)
Treasury stock purchased (in shares)					(303)
Cash dividends				(22,494)		(22,494)
Shares issued under ESPP		146				146
Shares issued under ESPP (in shares)	18,786
Stock-based compensation, net of forfeitures		2,970				2,970
Stock-based compensation, net of forfeitures (in shares)					(41,804)
Net proceeds from issuance of common stock	$ 4	4,226				4,230
Net proceeds from issuance of common stock (in shares)	447,020
Comprehensive income (loss)
Net income				16,746		16,746
Ending balance at Jun. 30, 2022	$ 1,633	$ 3,450,603		$ (2,489,814)	$ (88,504)	$ 873,918
Stockholders' Equity, Ending balance (in shares) at Jun. 30, 2022	163,385,390
Treasury stock, common shares, Ending balance (in shares) at Jun. 30, 2022					(7,740,919)	7,740,919