Earnings Per Share Level 4 (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Income (Loss) Attributable to Parent [Abstract]
Income from continuing operations attributable to common stockholders, basic																	$ 177,038	$ 234,162	$ 170,283
Income from continuing operations — diluted																	177,081	234,212	170,334
Net income attributable to common stockholders	$ 66,246		$ 47,727		$ 15,620		$ 47,445		$ 72,354		$ 47,448		$ 52,595		$ 61,375		177,038	233,772	172,469
After tax interest on convertible debt																	43	50	51
Income from discontinued operations, net									$ 0		$ 0		$ (390)		$ 0		0	(390)	2,186
Net income — diluted																	$ 177,081	$ 233,822	$ 172,520
Weighted average shares (denominator):
Weighted average shares — basic																	193,086	200,356	210,741
Convertible debt																	121	121	121
Weighted average shares — diluted																	196,042	204,450	214,200
Net income attributable to common stockholders, basic	$ 0.35	[1]	$ 0.25	[1]	$ 0.08	[1]	$ 0.24	[1]	$ 0.37	[1]	$ 0.24	[1]	$ 0.26	[1]	$ 0.30	[1]	$ 0.92	$ 1.17	$ 0.82
Net income attributable to common stockholders, diluted	$ 0.34	[1]	$ 0.24	[1]	$ 0.08	[1]	$ 0.24	[1]	$ 0.36	[1]	$ 0.23	[1]	$ 0.25	[1]	$ 0.30	[1]	0.90	1.14	0.81
Income from continuing operations attributable to common stockholders, per share, basic																		1.17	0.81
Income from continuing operations attributable to common stockholders, per share, diluted																		1.14	0.80
Income from discontinued operations per share, basic																	0.00	0	0.01
Income from discontinued operations per share, diluted																	$ 0.00	$ 0	$ 0.01
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount																	982,000	3,000	1,491,000
Stock Options [Member]
Weighted average shares (denominator):
Share based compensation																	2,823	3,973	3,338
Restricted Stock Units (RSUs) [Member]
Weighted average shares (denominator):
Share based compensation																	12	0	0

[1] Net income per share is computed independently for each of the quarters presented. Therefore, the sum of the quarters’ net income per share may not equal the total computed for the year.