Commercial Mortgage Banking - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Mortgage Banking [Abstract]
Percentage of controlling interest owned by the company in OMHHF	83.68%
Non-controlling interest	16.32%		16.32%
Number of related party	1
Prepayment costs	$ 1,500,000	$ 7,700,000	$ 1,800,000	$ 10,700,000
Custodial escrow accounts	251,600,000		251,600,000		251,400,000
Uninsured balance relation to escrow accounts	154,000,000		154,000,000
Fair value of servicing rights	40,700,000		40,700,000		40,100,000
Carrying value of loan servicing rights	$ 29,115,000	$ 27,665,000	$ 29,115,000	$ 27,665,000	$ 28,879,000	$ 26,983,000
Servicing rights are amortized using straight-line method	10 years