Business Segments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Segment	Sep. 30, 2013
Segment Reporting Information [Line Items]
Reportable business segments			3
Total revenues	$ 1,003,723	$ 665,320	$ 2,101,578	$ 1,610,555
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	$ 22,061		$ 22,061