Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014 Contract Office	Jun. 30, 2013	Jun. 30, 2014 Segment Residential Contract Office Branches	Jun. 30, 2013 Office	Dec. 31, 2012 Office
Summary Of Significant Accounting Policies [Line Items]
Real estate development and construction maximum family residential units			4
Real estate development and construction minimum family residential units			1
Number of real estate joint ventures currently involved			9
Number of full service banking branches			23	23	23
Number of loan production offices	1		1
Number of operating segment			1
Stock-based compensation expense	$ 235,000	$ 185,000	$ 463,000	$ 357,000
Tax benefit from compensation expense	33,000	19,000	55,000	38,000
Unrecognized compensation cost	992,000		992,000
Share based compensation expense recognized, years			4 years
Interest rate cap contracts outstanding	21		21
Interest payment in junior subordinated notes	35,000,000		35,000,000
Number of interest rate swap contracts			2
Minimum cumulative percentage change in anticipated cash flows			80.00%
Maximum cumulative percentage change in anticipated cash flows			125.00%
Amounts charged to current earnings	0		0
Interest Rate Swaps [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest payment in junior subordinated notes	35,000,000		35,000,000
Interest Rate Caps [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest payment in junior subordinated notes	$ 220,000,000		$ 220,000,000
AMSCO Inc [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage			51.00%