Nature of Operations and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		16 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Aug. 01, 2017	Dec. 15, 2015
Nature of Operations
Business Combination, Consideration Transferred		$ 71,700
Restricted Cash and Cash Equivalents, Current		0	$ 0
Restricted Cash and Cash Equivalents, Noncurrent		0	0
Allowance for doubtful accounts		1,500	1,300
Accumulated depreciation		$ 1,582,000	1,626,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 29,800
Percentage Of Expected Natural Gas Requirement Covered Under Contract			30.00%
Interest Costs Capitalized			$ 1,800	$ 900
Shelby paper machine interest cost capitalized			200
Entity Common Stock, Shares Outstanding						16,433,415
Land			$ 4,200
Common Stock
Nature of Operations
Common stock repurchase authorized							$ 100,000
Number of shares repurchased (in shares)	84,750				1,440,696
Treasury Stock Acquired, Average Cost Per Share	$ 57.53