Share-based Compensation - Additional Information (Detail) - USD ($)			1 Months Ended	12 Months Ended
	Apr. 01, 2019	Jan. 31, 2019	Aug. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015	Feb. 25, 2019	Jun. 29, 2004
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				1,301,314	1,175,887
Options exercisable				896,836
Income tax benefit related to expense				$ 3,500,000	$ 3,200,000	$ 3,400,000
Exercised stock option amount				2,800,000
Realized tax benefit amount				$ 300,000
Closing stock price				$ 46.18
Non-vested shares, vested in period				$ 2,700,000	0.0	0.0
Share-based compensation				21,540,000	18,930,000	12,557,000
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation				16,872,000	15,197,000	9,671,000
Transition and Retirement Agreement [Member] | General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation				$ 6,500,000
Global Spine [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Options outstanding				50,711
Options exercisable				0
Share based compensation, grant of restricted stock units			14,743
Share based compensation, vesting rights			25.00%
Global Spine [Member] | Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Common stock acquire under stock option			50,711
Options Medical Founder[Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unvested restricted stock and stock units outstanding		25,478
Share based compensation, grant of restricted stock units		25,478
Share based compensation, grant fair value of restricted stock units		$ 1,400,000
Share based compensation, vesting rights		33.33%
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
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				4,750,000
Options outstanding				1,067,947
Options exercisable				714,180
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				7,156
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				1,827,147
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				14,743
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				119,217
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				5,608
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				560,844
Market-based Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant of restricted stock units				60,722
Unamortized compensation expense				$ 3,800,000
Weighted-average period for unamortized compensation cost expected to be recognized				1 year 2 months 12 days
Aggregate intrinsic value of restricted stock outstanding				$ 11,900,000	14,200,000	10,200,000
Share-based compensation				$ 4,733,000	5,256,000	2,904,000
Common stock issued based on performance stock units				1
Percentage of performance to be achieved				100.00%
Performance period				3 years
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				25,500
Stock Option [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Service period				4 years
Unamortized compensation expense				$ 3,700,000
Weighted-average period for unamortized compensation cost expected to be recognized				1 year 8 months 12 days
Total intrinsic value of options exercised				$ 1,400,000	3,200,000	2,200,000
Aggregate intrinsic value of options outstanding				7,300,000	13,600,000	18,700,000
Aggregate intrinsic value of options exercisable				6,700,000	11,000,000.0	12,400,000
Share-based compensation				$ 4,054,000	3,061,000	2,388,000
Time-based Restricted Stock Awards and Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant of restricted stock units				319,189
Unamortized compensation expense				$ 15,300,000
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				$ 9,500,000	8,000,000.0	7,300,000
Aggregate intrinsic value of restricted stock outstanding				21,600,000	18,800,000	17,800,000
Share-based compensation				$ 11,084,000	$ 7,265,000	$ 5,540,000
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				47,077
Performance-based Restricted Stock Awards and Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant of restricted stock units				0	0	0
Share-based compensation					$ 1,998,000	$ 462,000
Performance-based Restricted Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant of restricted stock units							110,660
Unamortized compensation expense				$ 0
Non-vested shares, vested in period				3,200,000	0.0	4,900,000
Aggregate intrinsic value of restricted stock outstanding				0.0	2,900,000	3,000,000.0
Share-based compensation				0	400,000	500,000
Performance-based Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, grant of restricted stock units							55,330
Unamortized compensation expense				0
Aggregate intrinsic value of restricted stock outstanding				0.0	2,500,000	3,000,000.0
Share-based compensation				$ 0.0	$ 1,600,000	$ 0.0