Income Taxes - Summary of Differences Between Total Income Tax Expense Statutory Federal Income Tax Rate (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense Benefit [Line Items]
Corporate statutory rate	34.00%	34.00%	34.00%
Puerto Rico [Member]
Income Tax Expense Benefit [Line Items]
Corporate statutory rate	39.00%	39.00%	30.00%
Puerto Rico [Member] | Rate Prior to Retroactive Increase [Member]
Income Tax Expense Benefit [Line Items]
Corporate statutory rate		30.00%
Puerto Rico [Member] | Increase in Statutory Rate [Member]
Income Tax Expense Benefit [Line Items]
Corporate statutory rate		39.00%