Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation
Tax at federal statutory rate (as a percent)	35.00%	35.00%	35.00%
Permanent differences (as a percent)	(2.90%)	(1.60%)	(2.90%)
State income taxes (as a percent)	6.30%	2.00%	3.10%
Foreign taxes (as a percent)	(1.90%)	0.30%	2.50%
Other (as a percent)	0.30%	0.60%	1.40%
Effective income tax rate (as a percent)	36.80%	36.30%	39.10%