Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended		36 Months Ended
	Dec. 31, 2015	May. 16, 2012	May. 18, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capitalized stock-based compensation costs	$ 0			$ 0	$ 0
2011 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock available under the 2011 plan	4,000,000
2011 Equity Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Share-based compensation vesting period	One-third on each of the first three anniversaries of the date of grant
Weighted average period	1 year 3 months 18 days
Total unrecognized compensation cost	$ 2,000,000
2011 Equity Incentive Plan [Member] | Restricted Shares and Restricted Stock Units (RSU's) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation vesting period	One-third on each of the first three anniversaries of the date of grant
Weighted average period	1 year 8 months 12 days
Total unrecognized compensation cost	$ 14,600,000
2011 Equity Incentive Plan [Member] | Restricted Shares and Restricted Stock Units (RSU's) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of vesting possibilities	0.00%
2011 Equity Incentive Plan [Member] | Restricted Shares and Restricted Stock Units (RSU's) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of vesting possibilities	100.00%
Non-Employee Director Fee Plan [Member] | Common Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan expiration date	May 31, 2014
Weighted average period	3 months 18 days
Total unrecognized compensation cost	$ 200,000
Value of initial granted shares of common stock to new non employee director	$ 60,000
Vesting period of initial granted shares of common stock to new non employee director	Twelve equal quarterly installments, one-twelfth on the date of grant and an additional one-twelfth on each successive third monthly anniversary of the date of grant
Value of Annual Retainer to Non-Employee Director		$ 95,000	$ 125,000
Annual Retainer payable in cash to Non Employee Director	$ 55,000	$ 50,000	50,000
Amended vesting period of cash Annual retainer to non-employee chairman and committee members	Vested in four equal quarterly installments, one-fourth on the day following the annual meeting of shareholders, and an additional one-fourth on each successive third monthly anniversary of the date of grant
Vesting period of annual granted shares of common stock to non-employee director	Vests in eight equal quarterly installments, one-eighth on the day following the annual meeting of shareholders, and an additional one-eighth on each successive third monthly anniversary of the date of grant
Increased stock component of annual retainer	$ 25,000		$ 30,000
Vesting period for the annual equity award		2 years	1 year
Amended vesting period of annual granted shares of common stock to non-employee director	Four equal quarterly installments, one-fourth on the date of grant and an additional one-fourth on each successive third monthly anniversary of the date of grant
Additional annual cash award to be given to any non employee chairman of board	$ 100,000
Additional annual cash award to be given to Chairperson of the audit committee	20,000
Additional annual cash award to be given to audit committee members	10,000
Annual cash awards for the Chairpersons of the Compensation Committee, Finance Committee and Nominating and Corporate Governance Committee	12,500
Annual cash awards for the members of the Compensation Committee, Finance Committee and Nominating and Corporate Governance Committee	7,500
Increased additional annual cash award to Chairperson of Compensation Committee	15,000
Annual Retainer payable in stock to Non Employee Director	100,000
Increased cash component of annual retainer	$ 5,000
Deferred Compensation Plan [Member] | Common Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period	2 years
Total unrecognized compensation cost	$ 100,000
Percentage of contribution in respect of amounts deferred by certain senior management participants	50.00%
Vesting period of matching contributions and associated earnings	7 years
Deferred Compensation Plan [Member] | Common Stock Awards [Member] | Treasury Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock match associated with the deferred compensation plan carrying value	$ 1,600,000			1,500,000
Deferred Compensation Plan [Member] | Common Stock Awards [Member] | President, Chief Executive Officer and Executive Vice Presidents [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amounts deferred by certain senior management personnel	12,000
Deferred Compensation Plan [Member] | Common Stock Awards [Member] | Senior Vice President, Global Vice Presidents and Vice Presidents [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amounts deferred by certain senior management personnel	7,500
Deferred Compensation Plan [Member] | Accrued employee compensation and benefits
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrued employee compensation and benefits	$ 7,900,000			$ 7,000,000
2001 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan expiration date	Mar. 14, 2011