Stock-Based Compensation - Additional Information (Detail) (USD $)	9 Months Ended					3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Stock Options and Restricted Stock [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member]	Sep. 30, 2013 Employee Stock Incentive Plan [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Performance Shares [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Performance Shares [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Performance Shares [Member] Growth in Tangible Book Value per Share Plus Dividends [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Performance Shares [Member] Total Shareholder Return as Compared to Our Peer Group [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Stock Options and Restricted Stock [Member]	Sep. 30, 2013 Employee Stock Incentive Plan [Member] Stock Options and Restricted Stock [Member]	Sep. 30, 2014 Employee Stock Incentive Plan [Member] Stock Options and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive stock option's maximum term, years							3 years
Number of shares, awarded during the period				779,000	476,000		240,000					539,000
Award vesting rights as a percentage			33.333%					75.00%	25.00%
Average grant date fair value						$ 9.94				$ 9.10
Number of shares, available for grant				4,200,000
Stock-based compensation expense	$ 5,582,000	$ 4,743,000								$ 1,800,000	$ 1,400,000
Stock-based compensation amortization expense unrecognized	$ 10,800,000
Average remaining vesting, years	3 years