Reconciliation of Weighted Average Shares Used in Calculating Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Basic	48,243	48,551	48,201	49,034
Effect of exercise of stock options	82	1,016	91	1,061
Effect of assumed vesting of restricted stock	1,270	1,339	1,286	1,361
Effect of convertible notes subject to conversion		5,743	1,174	5,240
Effect of convertible notes warrants subject to conversion		1,946		1,541
Diluted	49,595	58,595	50,752	58,237