Earnings/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Oct. 31, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator for basic and diluted net income/(loss) per share:
Net income from continuing operations		$ 86,430	$ 102,467	$ 51,069	$ 24,284	$ 25,545	$ 31,668	$ (15,570)	$ (7,873)	$ 264,250	$ 33,770	$ 74,010
Income from discontinued operations, net of tax		6,214	10,679	7,935	9,535	4,537	(8,485)	9,999	9,559	34,363	15,610	47,854
Gain from sale of discontinued operations, net of tax	$ 2,700	2,742	0	0	0					2,742	0	0
Net income		$ 95,386	$ 113,146	$ 59,004	$ 33,819	$ 30,082	$ 23,183	$ (5,571)	$ 1,686	$ 301,355	$ 49,380	$ 121,864
Denominator (in shares):
Weighted-average shares for basic income/(loss) per share		76,271	79,467	79,403	79,028	79,125	79,761	80,473	80,179	78,542	79,885	80,854
Dilutive effect of stock options and restricted stock units										1,953	1,136	1,421
Weighted-average shares for diluted income/(loss) per share		78,371	81,402	80,646	80,525	80,356	80,914	80,473	81,277	80,495	81,021	82,275
Earnings Per Share, Basic (usd per share)
Net income from continuing operations (usd per share)		$ 1.13	$ 1.29	$ 0.64	$ 0.31	$ 0.32	$ 0.40	$ (0.19)	$ (0.10)	$ 3.36	$ 0.42	$ 0.92
Income from discontinued operations, net of tax (usd per share)		0.08	0.13	0.10	0.12	0.06	(0.11)	0.12	0.12	0.44	0.20	0.59
Gain from sale of discontinued operations, net of tax (usd per share)		0.04	0	0	0					0.03	0	0
Net income (usd per share)		1.25	1.42	0.74	0.43	0.38	0.29	(0.07)	0.02	3.83	0.62	1.51
Earnings Per Share, Diluted (usd per share)
Net income from continuing operations (usd per share)		1.10	1.26	0.63	0.30	0.32	0.39	(0.19)	(0.10)	3.28	0.42	0.90
Income from discontinued operations, net of tax (usd per share)		0.08	0.13	0.10	0.12	0.06	(0.10)	0.12	0.12	0.43	0.19	0.58
Gain from sale of discontinued operations, net of tax (usd per share)		0	0	0	0.03					0.03	0	0
Net income (usd per share)		$ 1.21	$ 1.39	$ 0.73	$ 0.42	$ 0.38	$ 0.29	$ (0.07)	$ 0.02	$ 3.74	$ 0.61	$ 1.48
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options excluded from weighted average diluted shares outstanding (less than)										100	100	100
PBRSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options excluded from weighted average diluted shares outstanding (less than)										100	100	100