Commercial Mortgage Banking - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) related_party	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Servicing Liability at Amortized Cost [Line Items]
Company owned OMHHF	83.68%
Prepayment costs	$ 25,700	$ 9,800	$ 14,500
Custodial escrow accounts	421,500	285,500
Uninsured balance relation to escrow accounts	301,300
Carrying value of loan servicing rights	$ 28,168	30,140	$ 28,879
Servicing rights are amortized using straight-line method	10 years
Mortgage Servicing Rights
Servicing Liability at Amortized Cost [Line Items]
Fair value of servicing rights	$ 41,800	42,300
Carrying value of loan servicing rights	$ 28,200	$ 30,100
OMHHF
Servicing Liability at Amortized Cost [Line Items]
Non-controlling interest	16.32%
Number of related party | related_party	1