Depreciation and Amortization - Depreciation and Amortization Expense for Property and Equipment and Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Property, Plant and Equipment [Line Items]
Total depreciation and amortization expense	$ 4,848	$ 4,625
Operating expenses [Member]
Property, Plant and Equipment [Line Items]
Total depreciation and amortization expense	4,732	4,551
Corporate general and administrative expenses [Member]
Property, Plant and Equipment [Line Items]
Total depreciation and amortization expense	$ 116	$ 74