Income Taxes - Statutory Rate and Provisions for Income Taxes Percent (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal Statutory Tax Rate	35.00%	35.00%	35.00%
State Income Taxes, net of federal benefit	3.80%	3.90%	3.50%
Nondeductible Expense	2.60%	2.50%	2.30%
Uncertain tax position	(3.30%)
Credits and other	(0.40%)		(0.90%)
Effective Tax Rate	37.70%	41.40%	39.90%