Common Stock - Schedule of Changes in Common Stock (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]
Balance, Shares beginning	34,048,366
Exercise of stock options, Shares	6,795	579,476	155,708
Acquisitions of treasury stock, Shares		(2,614,748)
Balance, Shares ending	34,056,468	34,048,366
Common stock at the beginning of the period	$ 406
Exercise of stock options	106	4,546	916
Exercise of warrants	19	7,064
Acquisitions of treasury stock		(51,000)	(28,125)
Total common stock outstanding at the end of the period	406	406
Common Stock [Member]
Class of Stock [Line Items]
Common stock at the beginning of the period	406	396
Exercise of stock options	0	6	2
Exercise of warrants	0	4
Acquisitions of treasury stock	0	0
Total common stock outstanding at the end of the period	$ 406	$ 406	$ 396
Common Stock Outstanding [Member]
Class of Stock [Line Items]
Balance, Shares beginning	34,048,366	35,635,357	37,907,575
Exercise of stock options, Shares	6,795	579,476	155,708
Exercise of warrants, Shares	1,307	448,281	52
Acquisitions of treasury stock, Shares		(2,614,748)	(2,432,477)
Balance, Shares ending	34,056,468	34,048,366	35,635,357