Property and Equipment - Property and Equipment at Cost (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment	$ 1,053,678	$ 1,045,769
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	5,445	7,548
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	71,926	108,784
Telephone and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	840,396	790,254
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	37,094	33,133
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	59,384	53,023
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 39,433	$ 53,027