Summary of Significant Accounting Policies - Additional Information (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Sep. 28, 2012	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Purchase of additional shares of OMHHF	$ 3,000,000
Purchase percentage of additional shares of OMHHF	16.32%
Company owned OMHHF		83.68%
Non-controlling interest		6,088,000	5,353,000
Carrying value of intangibles		31,700,000	31,700,000
Amortization of mortgage servicing rights period		10 years
Cash equivalents maximum maturity period of highly liquid investments		90 days
Minimum
Summary Of Significant Accounting Policies [Line Items]
Loan forgiven over service period		3 years
Minimum | Furniture, fixtures and equipment
Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization on straight-line basis		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Loan forgiven over service period		5 years
Maximum | Furniture, fixtures and equipment
Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization on straight-line basis		7 years
Securities
Summary Of Significant Accounting Policies [Line Items]
Number of business days for related transactions		3 days
Commodities
Summary Of Significant Accounting Policies [Line Items]
Number of business days for related transactions		1 day
Trademarks and Trade Name
Summary Of Significant Accounting Policies [Line Items]
Carrying value of intangibles		$ 31,700,000