Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
Federal									$ 27,410	$ 36,077	$ 39,649
State									9,515	6,357	7,053
Foreign									4,605	3,068	3,333
Deferred
Federal									3,179	6,093	260
State									263	544	13
Foreign									523	(338)	(1,142)
Income tax expense (benefit)	$ 5,293	$ 16,473	$ 16,476	$ 7,253	$ 10,829	$ 16,581	$ 16,712	$ 7,679	45,495	51,801	49,166
Income and loss from continuing operations before income taxes
Domestic									169,109	132,105	131,827
Foreign									3,019	12,313	7,073
Income before taxes	$ 18,050	$ 60,834	$ 60,562	$ 32,682	$ 23,914	$ 44,778	$ 44,926	$ 30,800	$ 172,128	$ 144,418	$ 138,900
Reconciliations between the statutory federal income tax rates and effective income tax rates
Federal tax rate									21.00%	35.00%	35.00%
State taxes, net of federal benefit									4.50%	3.20%	3.40%
Tax benefit of domestic manufacturing deduction									0.00%	(2.00%)	(2.50%)
Mandatory deemed repatriation of foreign earnings									0.00%	2.70%	0.00%
Change in U.S. tax rate applied to deferred taxes									0.00%	(1.90%)	0.00%
Change in U.S. tax rate applied to deferred taxes									1.30%	1.30%	(0.10%)
True-up of prior year tax returns to tax provision									(1.20%)	(0.50%)	(0.20%)
Difference between United States statutory and foreign local tax rates									0.50%	(0.80%)	(0.30%)
Change in uncertain tax position									(0.10%)	0.00%	(0.20%)
Other									(0.40%)	1.10%	(0.30%)
Effective income tax rate									26.40%	35.90%	35.40%