Income Taxes - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) Tax_Positions	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Income Tax Contingency [Line Items]
Deferred tax assets previously reserved under a valuation allowance	$ 9,100,000			$ 9,100,000
Valuation allowance		$ 4,582,000	$ 4,465,000
Provision (benefit) for income taxes		28,689,000	25,427,000	(10,549,000)
Excess tax benefits from stock compensation		3,117,000	$ 12,883,000	$ 1,466,000
Unrecognized tax benefits related to identified uncertain tax positions		$ 100,000
Unrecognized tax benefits number of tax matters | Tax_Positions		1
Total liabilities associated with tax benefit upon recognized		$ 100,000
Accrued Interest [Member]
Income Tax Contingency [Line Items]
Liabilities for uncertain tax portions		4,000
Accrued Penalties [Member]
Income Tax Contingency [Line Items]
Liabilities for uncertain tax portions		$ 14,000
Exit Full Valuation Allowance [Member]
Income Tax Contingency [Line Items]
Provision (benefit) for income taxes	$ 10,900,000
Earliest Tax Year [Member] | Federal Tax Jurisdiction [Member]
Income Tax Contingency [Line Items]
Tax years subject to examination		2012
Earliest Tax Year [Member] | Michigan [Member]
Income Tax Contingency [Line Items]
Tax years examined			2008
Latest Tax Year [Member] | Federal Tax Jurisdiction [Member]
Income Tax Contingency [Line Items]
Tax years subject to examination		2015
Latest Tax Year [Member] | Michigan [Member]
Income Tax Contingency [Line Items]
Tax years examined			2011