Income Taxes - U.S. Federal Statutory Income Tax Rate Reconciled to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	6.60%	3.80%	3.80%
Tax rate change	5.20%	7.80%	1.50%
Nondeductible transaction costs		0.90%
Nondeductible meals, entertainment and penalties	3.30%	4.30%	4.10%
Stock-based compensation	1.30%	4.50%	(0.10%)
Uncertain tax positions	0.20%	0.80%	(2.30%)
Tax credits	(2.20%)	(3.60%)	(4.30%)
Other	(2.20%)	(0.30%)	(0.10%)
Effective Income Tax Rate Reconciliation, Percent, Total	47.20%	53.20%	37.60%