Income Taxes Effective tax rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ 29,807	$ 24,395	$ 13,927
Income Tax Reconciliation, State and Local Income Taxes	1,795	2,661	981
Income Tax Reconciliation, Tax Credits	(1,014)	(5,861)	(1,591)
Income Tax Reconciliation, Deductions, Qualified Production Activities	(653)	(107)	(101)
Income Tax Reconciliation, Foreign Income Tax Rate Differential	$ (135)	$ 3,412	$ 39
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes	2.10%	3.90%	2.50%
Effective Income Tax Rate Reconciliation, Tax Credits	(1.20%)	(8.40%)	(4.00%)
Effective Income Tax Rate Reconciliation, Deductions, Qualified Production Activities	(0.80%)	(0.10%)	(0.20%)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	(0.10%)	(4.90%)	(0.10%)
Effective Income Tax Rate, Continuing Operations	25.90%	35.50%	33.80%
effective income tax rate reconciliation, ASU 2016-09	$ (7,720)	$ 0	$ 0
effective income tax rate reconciliation-percent, ASU 2016-09	(9.10%)	(0.00%)	(0.00%)