Taxes - Schedule of Change in Accounting Policy (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in Accounting Estimate [Line Items]
Income before income tax expense									$ 162,994	$ 234,574	$ 266,464
Income tax expense (benefit)									(40,871)	15,307	89,752
Net income	$ 80,327	$ 41,685	$ 48,749	$ 33,104	$ 45,418	$ 80,436	$ 56,196	$ 37,217	$ 203,865	$ 219,267	$ 176,712
Basic net income (loss) per share (in dollars per share)	$ 0.47	$ 0.24	$ 0.28	$ 0.19	$ 0.26	$ 0.47	$ 0.33	$ 0.21	$ 1.19	$ 1.27	$ 1.02
Diluted net income (loss) per share (in dollars per share)	$ 0.46	$ 0.24	$ 0.28	$ 0.19	$ 0.26	$ 0.45	$ 0.32	$ 0.21	$ 1.16	$ 1.24	$ 0.98
Deferred tax assets	$ 28,660								$ 449,519	$ 28,660
Deferred tax liabilities									332,344
Retained earnings	$ 646,214								753,268	$ 646,214
As computed under the previous accounting policy
Change in Accounting Estimate [Line Items]
Income before income tax expense									162,994
Income tax expense (benefit)									(393,317)
Net income									$ 556,311
Basic net income (loss) per share (in dollars per share)									$ 3.25
Diluted net income (loss) per share (in dollars per share)									$ 3.17
Deferred tax assets									$ 469,621
Deferred tax liabilities									0
Retained earnings									1,105,714
Effect of change | Change in accounting policy
Change in Accounting Estimate [Line Items]
Income before income tax expense									0
Income tax expense (benefit)									352,446
Net income									$ (352,446)
Basic net income (loss) per share (in dollars per share)									$ (2.06)
Diluted net income (loss) per share (in dollars per share)									$ (2.01)
Deferred tax assets									$ (20,102)
Deferred tax liabilities									332,344
Retained earnings									$ (352,446)