Note Net income per common share (Computation of net income (loss) per common share ("EPS"), basic and diluted) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Income (loss) from continuing operations	$ 92,945	$ 84,999
Net Income	92,945	84,999
Preferred stock dividends	(931)	(931)
Net income (loss) applicable to common stock	$ 92,014	$ 84,068
Average common shares outstanding	102,932,989	103,188,815
Average potential dilutive common shares	180,906	80,998
Average common shares outstanding - assuming dilution	103,113,895	103,269,813
Net Income per Common Share - Basic	$ 0.89	$ 0.81
Net Income per Common Share - Diluted	$ 0.89	$ 0.81