Reconciliation of Effective Income Tax Rate from Statutory Federal Income Tax Rate (Detail)	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Effective Income Tax Rate [Line Items]
Statutory federal income tax rate				35.00%	35.00%	35.00%
Valuation allowance				0.30%	0.70%	0.50%
Transaction costs				1.10%
State income taxes, net of federal benefit and tax credits				3.70%	4.60%	1.80%
Permanent differences				2.20%	1.10%	1.30%
Domestic production activities				(3.20%)	(3.10%)	(4.90%)
Federal research and experimentation credits				(2.30%)	(1.20%)	(1.70%)
Tax effects of foreign activities				5.20%	2.00%	(2.20%)
Tax-exempt income				(0.30%)	(0.10%)	(0.10%)
Provision to return adjustments				0.30%	0.30%
Non-deductible compensation				6.20%	3.30%	2.50%
Provision for uncertain tax positions				(2.30%)	(2.60%)	(0.70%)
Excess tax benefits related to share-based compensation				(20.10%)
Other				(2.50%)		(0.80%)
Effective income tax rate	40.10%	17.50%	22.90%	23.30%	40.00%	30.70%