Reconciliation of Weighted Average Shares Used in Calculating Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share Disclosure [Line Items]
Basic	48,158	49,522
Effect of exercise of stock options	99	1,117
Effect of assumed vesting of restricted stock	1,304	1,382
Effect of convertible notes subject to conversion	2,348	4,893
Effect of convertible notes warrants subject to conversion		1,137
Diluted	51,909	58,051