CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Deferred Stock Units	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
Balance beginning of period (in shares) at Dec. 31, 2018		105,087
Balance beginning of period at Dec. 31, 2018	$ (9,233)	$ 10,509	$ 1,138,216	$ 4,524	$ 1,167,928	$ (41,791)	$ (2,288,899)	$ 280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	102,709				102,681			28
Other comprehensive loss, net	1,776					1,776
Repurchases of common stock, net	(61,135)						(61,135)
Common stock issued under stock plans (in shares)		258
Common stock issued under stock plans	11,419	$ 26	11,393
Share-based compensation cost	6,334		6,266	68
Balance end of period (in shares) at Mar. 31, 2019		105,345
Balance end of period at Mar. 31, 2019	51,870	$ 10,535	1,155,875	4,592	1,270,609	(40,015)	(2,350,034)	308
Balance beginning of period (in shares) at Dec. 31, 2018		105,087
Balance beginning of period at Dec. 31, 2018	(9,233)	$ 10,509	1,138,216	4,524	1,167,928	(41,791)	(2,288,899)	280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	228,410
Other comprehensive loss, net	1,208
Balance end of period (in shares) at Jun. 30, 2019		105,478
Balance end of period at Jun. 30, 2019	171,549	$ 10,548	1,170,962	4,381	1,396,315	(40,583)	(2,370,377)	303
Balance beginning of period (in shares) at Mar. 31, 2019		105,345
Balance beginning of period at Mar. 31, 2019	51,870	$ 10,535	1,155,875	4,592	1,270,609	(40,015)	(2,350,034)	308
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	125,701				125,706			(5)
Other comprehensive loss, net	(568)					(568)
Repurchases of common stock, net	(20,343)						(20,343)
Common stock issued under stock plans (in shares)		133
Common stock issued under stock plans	7,991	$ 13	8,556	(578)
Deferred stock units activity	0		(324)	324
Share-based compensation cost	6,898		6,855	43
Balance end of period (in shares) at Jun. 30, 2019		105,478
Balance end of period at Jun. 30, 2019	$ 171,549	$ 10,548	1,170,962	4,381	1,396,315	(40,583)	(2,370,377)	303
Balance beginning of period (in shares) at Dec. 31, 2019	105,711	105,711
Balance beginning of period at Dec. 31, 2019	$ 177,825	$ 10,571	1,213,517	4,462	1,595,648	(46,182)	(2,600,543)	352
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	111,856				111,827			29
Other comprehensive loss, net	(9,064)					(9,064)
Repurchases of common stock, net	(187,767)						(187,767)
Common stock issued under stock plans (in shares)		203
Common stock issued under stock plans	9,750	$ 20	9,730
Share-based compensation cost	7,284		7,238	46
Balance end of period (in shares) at Mar. 31, 2020		105,914
Balance end of period at Mar. 31, 2020	$ 108,055	$ 10,591	1,230,485	4,508	1,705,646	(55,246)	(2,788,310)	381
Balance beginning of period (in shares) at Dec. 31, 2019	105,711	105,711
Balance beginning of period at Dec. 31, 2019	$ 177,825	$ 10,571	1,213,517	4,462	1,595,648	(46,182)	(2,600,543)	352
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	260,852
Other comprehensive loss, net	$ (10,850)
Balance end of period (in shares) at Jun. 30, 2020	106,031	106,031
Balance end of period at Jun. 30, 2020	$ 273,400	$ 10,603	1,247,456	5,402	1,854,586	(57,032)	(2,788,052)	437
Balance beginning of period (in shares) at Mar. 31, 2020		105,914
Balance beginning of period at Mar. 31, 2020	108,055	$ 10,591	1,230,485	4,508	1,705,646	(55,246)	(2,788,310)	381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	148,996				148,940			56
Other comprehensive loss, net	(1,786)					(1,786)
Issuances of common stock, net	258						258
Common stock issued under stock plans (in shares)		117
Common stock issued under stock plans	10,080	$ 12	10,068
Deferred stock units activity	0		(894)	894
Share-based compensation cost	$ 7,797		7,797
Balance end of period (in shares) at Jun. 30, 2020	106,031	106,031
Balance end of period at Jun. 30, 2020	$ 273,400	$ 10,603	$ 1,247,456	$ 5,402	$ 1,854,586	$ (57,032)	$ (2,788,052)	$ 437