Earnings Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share Reconciliation
Net income	$ 31,991	$ 29,520	$ 62,332	$ 63,355
Basic weighted average number of common shares outstanding (in shares)	232,565,404	200,472,592	232,452,716	200,301,438
Plus: Common stock equivalents (in shares)	21,212	0	5,032	0
Diluted weighted average number of common shares outstanding (in shares)	232,586,616	200,472,592	232,457,748	200,301,438
Earnings per common share:
Basic (in usd per share)	$ 0.14	$ 0.15	$ 0.27	$ 0.32
Diluted (in usd per share)	$ 0.14	$ 0.15	$ 0.27	$ 0.32
Anti-dilutive common stock options and warrants (in shares)	6,100,000	6,600,000	6,100,000	6,600,000