ISSUANCE OF 7 1/2% SERIES E PERPETUAL PREFERRED SHARES AND REDEMPTION OF SERIES A AND B PERPETUAL PREFERRED SHARES - Offerings (Detail) (USD $)	1 Months Ended		3 Months Ended
	May 09, 2014 Subsequent Event [Member]	May 31, 2013 Cumulative Redeemable Preferred Stock, Series E [Member]	Mar. 31, 2014 Cumulative Redeemable Preferred Stock, Series E [Member]
Class of Stock [Line Items]
Redeemable preferred stock, shares issued (in shares)		6,800,000
Redeemable preferred stock, face value		$ 170,000,000
Preferred Stock, Dividend Rate, Percentage (in hundredths)		7.50%
Redeemable preferred stock, liquidation preference per share (in dollars per share)		$ 25.00
Proceeds from Issuance of Redeemable Preferred Stock	2,200,000	164,300,000	1,300,000
Cash on hand paid to redeem preferred stock		$ 42,700,000
Additional shares issued (in shares)	92,000		56,000
Average cost per share (in dollars per share)	$ 23.96		$ 23.83