Stockholders' Equity - Cash Dividends Declared to Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Jul. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Oct. 28, 2015
Record Date	Nov. 18, 2015
Payment Date	Dec. 10, 2015
Per Share Amount (usd per share)		$ 0.125
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per Share Amount (usd per share)	$ 0.375
Total Payment	$ 8,094
Common Stock [Member] | Installment One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Mar. 04, 2015
Record Date	Mar. 18, 2015
Payment Date	Mar. 30, 2015
Per Share Amount (usd per share)	$ 0.125
Total Payment	$ 2,715
Common Stock [Member] | Installment Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Apr. 30, 2014
Record Date	May 22, 2014
Payment Date	Jun. 25, 2014
Per Share Amount (usd per share)	$ 0.125
Total Payment	$ 2,713
Common Stock [Member] | Installment Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Jul. 28, 2014
Record Date	Aug. 19, 2014
Payment Date	Sep. 10, 2014
Per Share Amount (usd per share)	$ 0.125
Total Payment	$ 2,666