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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator for basic net income per common share: [Abstract]
Net income	$ 36,564	$ 29,894	$ 74,955	$ 64,812
Redemption premiums paid on Series A and Series B preferred shares	0	(19,924)	0	(19,924)
Preferred share dividends	(3,449)	(5,867)	(6,687)	(11,137)
Earnings participation of unvested stock awards	(12)	(32)	(36)	(64)
Numerator for basic net income per common share	33,103	4,071	68,232	33,687
Denominator for basic net income per common share: [Abstract]
Weighted average common shares outstanding (in shares)	95,767	95,616	95,772	95,588
Average unvested stock awards outstanding (in shares)	(368)	(490)	(398)	(515)
Denominator for basic net income per common share (in shares)	95,399	95,126	95,374	95,073
Basic net income per common share (in dollars per share)	$ 0.35	$ 0.04	$ 0.72	$ 0.35
Numerator for diluted net income per common share: [Abstract]
Net income available to common stockholders	33,103	4,071	68,232	33,687
Dividends on dilutive convertible preferred shares	0	0	0	44
Numerator for diluted net income per common share	$ 33,103	$ 4,071	$ 68,232	$ 33,731
Denominator for diluted net income per common share: [Abstract]
Basic weighted average common shares outstanding (in shares)	95,399	95,126	95,374	95,073
Net effect of dilutive equity awards	227	148	209	134
Net effect of dilutive convertible preferred shares (in shares)	0	123	0	152
Denominator for diluted net income per common share (in shares)	95,626	95,397	95,583	95,359
Diluted net income per common share (in dollars per share)	$ 0.35	$ 0.04	$ 0.71	$ 0.35