Statement of Cash Flows - Noncash Investing and Financing Activities - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Cash Flow Elements [Abstract]
Value of shares tendered for stock options exercised	$ 92,000	$ 8,400,000	$ 1,330,000
Shares tendered for stock options exercised	1,562	176,114	33,286
Shares issued related to the Company's performance stock award plan	48,973	84,568	108,104
Value of shares issued related to Company's performance stock award plan	2,999,000	3,659,000	3,836,000
Noncash investing activities incurred for fixed asset acquisitions	$ 11,772,000	$ 10,467,000	$ 11,723,000