Income Taxes Income Taxes Discussion (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent			29.90%	31.00%
Income tax expense	$ 8,289	$ 8,652	$ 24,805	$ 23,716
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate			35.00%	35.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount			$ 300