Condensed Consolidated Balance Sheet (Parenthetical) (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Mar. 31, 2012 As Reported [Member]	Mar. 31, 2011 As Reported [Member]	Mar. 31, 2012 Adjustment [Member]	Mar. 31, 2011 Adjustment [Member]	Mar. 31, 2012 Restated [Member]	Mar. 31, 2011 Restated [Member]
Allowance for doubtful accounts	$ 24,510	$ 26,221	$ 34,056			$ 26,889	$ 35,005
Common Stock ,par value	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common Stock ,shares authorized	120,000,000	120,000,000	120,000,000	120,000,000	120,000,000	120,000,000	120,000,000
Common Stock ,shares issued	72,740,302	73,125,230	72,716,235	73,125,230	72,716,235	73,125,230	72,716,235
Common Stock ,shares outstanding	72,740,302	73,125,230	72,716,235	73,125,230	72,716,235	73,125,230	72,716,235
Preferred Stock ,par value	$ 0.01	$ 0.01		$ 0.01		$ 0.01
Preferred Stock ,shares authorized	1,000,000	1,000,000		1,000,000		1,000,000
Preferred Stock , shares issued	0	0		0		0
Preferred Stock , shares outstanding	0	0		0		0
Treasury Stock,shares	246,037	246,037	246,037	246,037	246,037	246,037	246,037