Earnings Per Common Share (Basic and Diluted Earnings Per Common Share) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Earnings Per Common Share [Line Items]
Net income attributable to controlling interests	$ 17,504		$ 8,960		$ 31,759		$ 19,862
Preferred dividends and discount accretion of preferred stock	3,442		3,419		6,878		6,834
Net income available to common stockholders	14,062		5,541		24,881		13,028
Earnings allocated to participating stockholders(1)	263	[1]	75	[1]	430	[1]	144	[1]
Earnings allocated to common stockholders	13,799		5,466		24,451		12,884
Weighted-average common shares outstanding	70,956		70,428		70,868		70,388
Basic earnings per common share	$ 0.19		$ 0.08		$ 0.35		$ 0.18
Earnings allocated to common stockholders (2)	$ 13,799	[2]	$ 5,466	[2]	$ 24,450	[2]	$ 12,883	[2]
Weighted-average common shares outstanding	70,956		70,428		70,868		70,388
Dilutive effect of stock awards (3)	191	[3]	235	[3]	173	[3]	214	[3]
Weighted-average diluted common shares outstanding	71,147		70,663		71,041		70,602
Diluted earnings per common share	$ 0.19		$ 0.08		$ 0.34		$ 0.18
Stock Options [Member]
Earnings Per Common Share [Line Items]
Total antidilutive shares	3,834		3,626		3,854		3,620
Restricted Stock [Member]
Earnings Per Common Share [Line Items]
Total antidilutive shares	78		175		82		216
Warrants [Member]
Earnings Per Common Share [Line Items]
Total antidilutive shares	645		645		645		645

[1] Participating stockholders are those that hold unvested shares or units that contain nonforfeitable rights to dividends or dividend equivalents. Such shares or units are considered participating securities (i.e., the Company's deferred stock units and nonvested restricted stock awards and restricted stock units, excluding certain awards with forfeitable rights to dividends).

[2] Earnings allocated to common stockholders for basic and diluted earnings per share may differ under the two-class method as a result of adding common stock equivalents for options and warrants to dilutive shares outstanding, which alters the ratio used to allocate earnings to common stockholders and participating securities for the purposes of calculating diluted earnings per share.

[3] The following table presents outstanding non-participating securities that were not included in the computation of diluted earnings per common share because their inclusion would have been antidilutive for the periods presented.