Supplemental Cash Flow Disclosures - Non-Cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Supplemental Cash Flow Disclosures Noncash Investing And Financing Activities [Abstract]
Capital property and equipment acquired on account, but not paid as of December 31	$ 2,668	$ 459	$ 341
Retirement Savings Plan	690	602	0
Conversion of Debentures	0	535	295
Performance Incentive Plan	1,594	1,533	850
Capital Lease Obligation	4,824	6,130	7,126
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 30,164	$ 0	$ 0