Capital Stock - Summary of Common Stock Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances (in shares)	(37,736,578)
Stock options exercised (in shares)	620,646	341,063	64,752
Stock options forfeitures, Shares		(12,753)	(28,708)
Ending Balances (in shares)	(38,222,928)	(37,736,578)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances (in shares)	(62,081,391)	(62,081,391)	(62,081,391)
Ending Balances (in shares)	(62,081,391)	(62,081,391)	(62,081,391)
Beginning Balances	$ (172,681)	$ (157,643)	$ (148,401)
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options		478	597
Ending Balances	$ (194,953)	$ (172,681)	$ (157,643)
Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances (in shares)	(24,344,813)	(24,708,917)	(24,633,081)
Ending Balances (in shares)	(23,858,463)	(24,344,813)	(24,708,917)
Beginning Balances	$ (287,501)	$ (293,318)	$ (284,805)
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options		0	0
Ending Balances	(296,081)	$ (287,501)	$ (293,318)
Noncontrolling Interest \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	450
Noncontrolling Interest \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	$ 0
Restricted Stock \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards (in shares)	0	0	0
Restricted stock forfeitures (in shares)	0	0	0
Restricted stock awards	$ 422	$ 355	$ 404
Share-based compensation expense	4,746	3,604	3,461
Stock compensation awards forfeited, Value	$ (49)	$ (148)	$ (426)
Restricted Stock \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards (in shares)	34,798	29,836	34,624
Restricted stock forfeitures (in shares)	(690)	(2,800)	(18,468)
Restricted stock awards	$ 422	$ 355	$ 404
Share-based compensation expense	0	0	0
Stock compensation awards forfeited, Value	$ (6)	$ 0	$ 0
Stock Options \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)	0	0	0
Stock options forfeitures, Shares		0	0
Share-based compensation expense	$ 380	$ 2,484	$ 2,572
Stock compensation awards forfeited, Value		(25)	(118)
Stock options exercised	$ 10,901	$ 5,617	$ 1,714
Stock Options \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)	620,646	341,063	64,752
Stock options forfeitures, Shares		0	0
Share-based compensation expense	$ 0	$ 0	$ 0
Stock compensation awards forfeited, Value		0	0
Stock options exercised	$ 7,564	$ 6,859	$ 216
Performance Stock \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock forfeitures (in shares)		0	0
Performance stock issued (in shares)	0	0	0
Share-based compensation expense	$ 6,687	$ 3,324	$ 2,265
Stock compensation awards forfeited, Value		(28)	(155)
Performance stock issued	$ (866)	$ (371)	$ (616)
Performance Stock \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock forfeitures (in shares)		0	0
Performance stock issued (in shares)	72,504	31,093	52,839
Share-based compensation expense	$ 0	$ 0	$ 0
Stock compensation awards forfeited, Value		0	0
Performance stock issued	$ (866)	$ (371)	$ (616)
Employee Stock Purchase Plan \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee Stock Purchase Plan, Shares	0	0	0
Employee Stock Purchase Plan, Value	$ 445	$ 458	$ 352
Employee Stock Purchase Plan \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee Stock Purchase Plan, Shares	7,127	9,500	11,517
Employee Stock Purchase Plan, Value	$ 87	$ 113	$ 136
Stock Compensation Plan \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)	0	0	0
Treasury shares purchased for stock compensation programs	$ 0	$ 0	$ 0
Stock Compensation Plan \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)	(79,094)	(44,588)	(71,100)
Treasury shares purchased for stock compensation programs	$ (5,732)	$ (1,881)	$ (2,781)
Share Repurchase Program, May 2015 \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)	0		0
Treasury shares purchased for stock compensation programs	$ 0		$ 0
Share Repurchase Program, May 2015 \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)	(168,941)		(150,000)
Treasury shares purchased for stock compensation programs	$ (11,781)		$ (7,104)
Share Repurchase Program, May 2015 \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)	(168,941)
Share Repurchase Program, May 2015 \| Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares purchased (in shares)		0	(150,000)

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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