Share-based Compensation - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended
	Apr. 01, 2019	Sep. 30, 2020	Aug. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2015	Feb. 25, 2019	Dec. 31, 2017	Jun. 29, 2004
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				1,491,019	1,301,314
Options exercisable				908,042
Income tax benefit related to expense				$ 3,200,000	$ 3,500,000	$ 3,200,000
Exercised stock option amount				2,700,000
Realized tax benefit amount				$ 100,000
Closing stock price				$ 42.98
Non-vested shares, vested in period				$ 0.0	2,700,000	0.0
Share-based compensation				16,207,000	21,540,000	18,930,000
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation				10,624,000	16,872,000	15,197,000
Transition and Retirement Agreement [Member] | General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation				$ 0	$ 6,500,000
President and Chief Executive Officer [Member] | Transition and Retirement Agreement [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Transition consulting services payable per month								$ 40,000
President and Chief Executive Officer [Member] | Transition and Retirement Agreement [Member] | First Anniversary [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant date fair market value of restricted stock units	$ 2,000,000.0
Global Spine [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				50,711
Options exercisable				12,677
Share based compensation grants of restricted stock unit			14,743
Global Spine [Member] | Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock acqure under stock option			50,711
Global Extremities [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				32,945
Options exercisable				0
Share based compensation grants of restricted stock unit		10,624
Global Extremities [Member] | Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock acqure under stock option		32,945
2012 LTIP Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Award Contractual term				10 years
Amount of shares reserved for issuance				5,850,000
Options outstanding				1,244,863
Options exercisable				732,865
2004 LTIP [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Amount of shares reserved for issuance										3,100,000
Spinal Kinetics Inducement Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				0
Number of shares reserved for employees					51,705
Stock Purchase Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Amount of shares reserved for issuance				2,350,000
Maximum percentage of compensation eligible employees to be deducted for purchase of common stock				25.00%
Purchase price of shares equivalent to fair market value				85.00%
Shares issued under stock purchase plan				1,991,738
Stock Purchase Plan [Member] | Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of compensation eligible employees to be deducted for purchase of common stock				1.00%
Restricted Stock [Member] | Global Spine [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding				11,058
Restricted Stock [Member] | Global Extremities [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding				10,624
Restricted Stock [Member] | 2012 LTIP Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding				46,619
Restricted Stock [Member] | Spinal Kinetics Inducement Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding				2,669
Restricted Stock Units [Member] | 2012 LTIP Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding				697,495
Market-based Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation grants of restricted stock unit				158,238
Unamortized compensation expense				$ 6,500,000
Weighted-average period for unamortized compensation cost expected to be recognized				1 year 7 months 6 days
Aggregate intrinsic value of restricted stock outstanding					$ 11,800,000	11,900,000			$ 14,200,000
Share-based compensation				$ 3,509,000	4,733,000	5,256,000
Common stock issued based on performance stock units				1
Percentage of performance to be achieved				100.00%
Performance period				3 years
Share based compensation, fair market value of restricted stock units vested				$ 1,400,000	0.0	0.0
Market-based Restricted Stock Units [Member] | Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of performance to be achieved				200.00%
Market-based Restricted Stock Units [Member] | Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of performance to be achieved				50.00%
Staff Share Option Plan [Member] | 2004 LTIP [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				12,500
Stock Option [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Service period				4 years
Unamortized compensation expense				$ 3,600,000
Weighted-average period for unamortized compensation cost expected to be recognized				1 year 8 months 12 days
Total intrinsic value of options exercised				$ 900,000	1,400,000	3,200,000
Aggregate intrinsic value of options outstanding				9,100,000	7,300,000	13,600,000
Aggregate intrinsic value of options exercisable				3,700,000	6,700,000	11,000,000.0
Share-based compensation				$ 2,571,000	4,054,000	3,061,000
Time-based Restricted Stock Awards and Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation grants of restricted stock unit				250,459
Unamortized compensation expense				$ 12,000,000.0
Weighted-average period for unamortized compensation cost expected to be recognized				2 years 6 months
Vesting period				4 years
Non-vested shares, vested in period				$ 6,500,000	9,500,000	8,000,000.0
Aggregate intrinsic value of restricted stock outstanding				21,200,000	21,600,000	18,800,000
Share-based compensation				$ 8,485,000	$ 11,084,000	$ 7,265,000
Restricted Stock Unit with Deferred Delivery (DSUs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period				1 year
Awards vested but not settled				74,036
Performance-based Restricted Stock Awards and Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation grants of restricted stock unit				0	0	0
Share-based compensation						$ 1,998,000
Performance-based Restricted Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation grants of restricted stock unit							110,660
Unamortized compensation expense				$ 0
Non-vested shares, vested in period				0.0	$ 3,200,000	0.0
Aggregate intrinsic value of restricted stock outstanding				0.0	0.0	2,900,000
Share-based compensation				0	0	400,000
Performance-based Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation grants of restricted stock unit							55,330
Unamortized compensation expense				0
Aggregate intrinsic value of restricted stock outstanding				0.0	0.0	2,500,000
Share-based compensation				$ 0.0	$ 0.0	$ 1,600,000