Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share Reconciliation
Net income available to common shareholders	$ 41,045	$ 33,937	$ 112,665	$ 96,269
Basic weighted average number of common shares outstanding (in shares)	254,473,994	232,737,953	254,310,769	232,548,840
Plus: Common stock equivalents (in shares)	466,313	42,266	387,824	16,855
Diluted weighted average number of common shares outstanding (in shares)	254,940,307	232,780,219	254,698,593	232,565,695
Earnings per common share:
Basic (in usd per share)	$ 0.16	$ 0.15	$ 0.44	$ 0.41
Diluted (in usd per share)	$ 0.16	$ 0.15	$ 0.44	$ 0.41
Anti-dilutive common stock options and warrants (in shares)	4,600,000	5,000,000	4,600,000	5,000,000