Transactions with Affiliates (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Chairman and Chief Executive Officer, and Certain Family Partnerships and Affiliates [Member]
Related Party Transaction [Line Items]
Investment commitments with related party	$ 22,700,000	$ 24,600,000
Due to related parties, current	42,000	58,000
Overhead recovery from related parties	152,000	145,000	160,000
Expense reimbursements from related parties	152,000	145,000	160,000
Other Affiliated Entities [Member]
Related Party Transaction [Line Items]
Overhead recovery from related parties	98,000	118,000	117,000
Expense reimbursements to related parties	64,000	42,000	43,000
Expense reimbursements from related parties	98,000	118,000	117,000
Estimated annual rental expense	480,000
Lease Term	7 years
Rent expense paid	$ 442,000