Unused Available Lines of Credit (Details Textual) (USD $)	Dec. 31, 2012 Unsecured Debt [Member]	Dec. 31, 2012 Unsecured Debt [Member] US Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] Wells Fargo Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] PNC Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] Frost National Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] JPM Chase Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] UMB Bank [Member]	Dec. 31, 2012 Unsecured Debt [Member] Bank Of America [Member]	Jan. 01, 2013 Secured Debt [Member] UMB Bank [Member]	Dec. 31, 2012 Secured Debt [Member] Federal Home Loan Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 108,000,000	$ 20,000,000	$ 15,000,000	$ 12,000,000	$ 10,000,000	$ 6,000,000	$ 25,000,000	$ 20,000,000	$ 50,000,000	$ 150,129,000