Earnings Per Common Share - Calculation of Both Basic and Diluted Earnings Per Common Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 33,835	$ 31,310
Basic weighted-average number of common shares outstanding	200,128,384	198,924,995
Diluted weighted-average number of common shares outstanding	200,128,384	198,924,995
Earnings per common share:
Basic	$ 0.17	$ 0.16
Diluted	$ 0.17	$ 0.16