Amortizable Intangible Assets - Additional Information (Detail) (USD $)	Mar. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense estimated, year one (2013)	$ 64,101,000
Amortization expense estimated, year two (2014)	63,039,000
Amortization expense estimated, year three (2015)	61,749,000
Amortization expense estimated, year four (2016)	57,169,000
Amortization expense estimated, year five (2017)	$ 54,457,000