NET INCOME PER COMMON SHARE - Basic and Diluted Net Income Per Common Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Numerator for basic net income per common share: [Abstract]
Net income	$ 24,702		$ 40,037		$ 89,514		$ 128,542
Redemption premiums paid on Series A and Series B preferred shares*	0	[1]	0	[1]	(19,924)	[1]	0	[1]
Preferred share dividends	(3,188)		(5,270)		(14,325)		(15,751)
Unvested stock award participation in earnings	(32)		(91)		(96)		(296)
Numerator for basic net income per common share	21,482		34,676		55,169		112,495
Denominator for basic net income per common share: [Abstract]
Weighted average common shares outstanding (in shares)	95,761		98,581		95,647		94,324
Average unvested stock awards outstanding (in shares)	(493)		(510)		(508)		(516)
Denominator for basic net income per common share (in shares)	95,268		98,071		95,139		93,808
Basic net income per common share (in dollars per share)	$ 0.23		$ 0.35		$ 0.58		$ 1.20
Numerator for diluted net income per common share: [Abstract]
Net income available to common stockholders	21,482		34,676		55,169		112,495
Dividends on dilutive convertible preferred shares	0		75		44		223
Numerator for diluted net income per common share	$ 21,482		$ 34,751		$ 55,213		$ 112,718
Denominator for diluted net income per common share: [Abstract]
Basic weighted average common shares outstanding (in shares)	95,268		98,071		95,139		93,808
Net effect of dilutive stock and option awards (in shares)	148		132		133		119
Net effect of dilutive convertible preferred shares (in shares)	0		309		101		309
Denominator for diluted net income per common share (in shares)	95,416		98,512		95,373		94,236
Diluted net income per common share (in dollars per share)	$ 0.23		$ 0.35		$ 0.58		$ 1.20

[1] The Series A and Series B preferred shares were redeemed on June 13, 2013 – See NOTE 9.