Stockholders' Equity - Schedule of Quarterly Cash Dividends to Common Stockholders (Detail) (USD $)	1 Months Ended	3 Months Ended				6 Months Ended
	May 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Equity [Abstract]
Dividend record date	Jun. 20, 2014	Jun. 20, 2014	Mar. 20, 2014	Dec. 20, 2013
Dividend payable date	Jul. 01, 2014	Jul. 01, 2014	Apr. 01, 2014	Jan. 03, 2014
Cash dividends declared	$ 0.21	$ 0.21	$ 0.20	$ 0.20	$ 0.20	$ 0.41	$ 0.20