Notes and Bonds Payable (Details 5) (Mortgage notes payable [Member], USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Mortgage Notes 7.765% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	$ 4,700,000
Effective Interest rate	7.765%	[1]
Maturity Date	2017-01
Collateral	MOB	[2]
Principal and interest payments	Monthly/20-yr amort.	[3]
Principal and interest amortization period	20 years
Investment in Collateral	11,800,000
Mortgage notes payable carrying amount	1,600,000		1,900,000
Mortgage Notes 5.550% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	1,800,000
Effective Interest rate	5.55%	[1]
Maturity Date	2030-10
Collateral	OTH	[2]
Principal and interest payments	Monthly/27-yr amort.	[3]
Principal and interest amortization period	27 years
Investment in Collateral	7,900,000
Mortgage notes payable carrying amount	1,600,000		1,600,000
Mortgage Notes 5.490% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	15,100,000
Effective Interest rate	5.49%	[1]
Maturity Date	2016-01
Collateral	MOB	[2]
Principal and interest payments	Monthly/10-yr amort.	[3]
Principal and interest amortization period	10 years
Investment in Collateral	32,700,000
Mortgage notes payable carrying amount	12,700,000		13,100,000
Mortgage Notes 6.480% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	17,400,000	[4]
Effective Interest rate	6.48%	[1],[4]
Maturity Date	2015-05	[4]
Collateral	MOB	[2],[4]
Principal and interest payments	Monthly/10-yr amort.	[3],[4]
Principal and interest amortization period	10 years	[4]
Investment in Collateral	19,900,000	[4]
Mortgage notes payable carrying amount	14,600,000	[4]	14,500,000	[4]
Unaccreted discount	2,700,000
Mortgage Notes 6.110% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	12,000,000	[5]
Effective Interest rate	6.11%	[1],[5]
Maturity Date	2015-07
Collateral	2 MOBs	[2],[5]
Principal and interest payments	Monthly/10-yr amort.	[3],[5]
Principal and interest amortization period	10 years
Investment in Collateral	19,500,000	[5]
Mortgage notes payable carrying amount	9,900,000	[5]	9,800,000	[5]
Unaccreted discount	2,100,000
Mortgage Notes 7.650% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	15,200,000	[6]
Effective Interest rate	7.65%	[1],[6]
Maturity Date	2020-07	[6]
Collateral	MOB	[2],[6]
Principal and interest amortization period	11 years
Investment in Collateral	20,200,000	[6]
Mortgage notes payable carrying amount	12,800,000	[6]	12,800,000	[6]
Unaccreted discount	2,400,000
Period for monthly installments of interest	24 months
Mortgage Notes 6.810% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	1,500,000	[7]
Effective Interest rate	6.81%	[1],[7]
Maturity Date	2016-07	[7]
Collateral	MOB	[2],[7]
Principal and interest payments	Monthly/9-yr amort.	[3],[7]
Principal and interest amortization period	9 years	[7]
Investment in Collateral	2,200,000	[7]
Mortgage notes payable carrying amount	1,100,000	[7]	1,100,000	[7]
Unaccreted discount	200,000
Mortgage Notes 6.430% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	12,900,000	[8]
Effective Interest rate	6.43%	[1],[8]
Maturity Date	2021-02	[8]
Collateral	MOB	[2],[8]
Principal and interest payments	Monthly/12-yr amort.	[3],[8]
Principal and interest amortization period	12 years	[8]
Investment in Collateral	20,600,000	[8]
Mortgage notes payable carrying amount	11,300,000	[8]	11,400,000	[8]
Unaccreted discount	1,000,000
Mortgage Notes 7.250% [Member] | Investment Fund [Member]
Debt Instrument [Line Items]
Mortgage notes	80,000,000
Effective Interest rate	7.25%	[1]
Maturity Date	2016-12
Collateral	15 MOBs	[2]
Principal and interest payments	Monthly/30-yr amort.(16)	[3],[9]
Principal and interest amortization period	30 years
Investment in Collateral	155,800,000
Mortgage notes payable carrying amount	77,500,000		78,400,000
Option to extend maturity	two, one-year floating rate extension terms
Number of terms to extend maturity	2	[9]
Period for extension of initial term	1 year	[9]
Mortgage Notes 5.530% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,000,000
Effective Interest rate	5.53%	[1]
Maturity Date	2018-01
Collateral	MOB	[2]
Principal and interest payments	Monthly/15-yr amort.	[3]
Principal and interest amortization period	15 years
Investment in Collateral	14,600,000
Mortgage notes payable carrying amount	3,000,000		3,500,000
Mortgage Notes 6.550% [Member] | Investment Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	15,900,000	[10]
Effective Interest rate	6.55%	[1],[10]
Maturity Date	2013-04	[10]
Collateral	MOB	[10],[2]
Principal and interest payments	Monthly/30-yr amort	[10],[11],[3]
Principal and interest amortization period	30 years	[10]
Investment in Collateral	23,400,000	[10]
Mortgage notes payable carrying amount	14,900,000	[10]	15,200,000	[10]
Unamortized portion of premium	500,000
Period for extension of initial term	3 years	[11]
Interest rate on senior notes	6.75%	[11]
Mortgage Notes 5.250% [Member] | Investment Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	4,600,000
Effective Interest rate	5.25%	[1]
Maturity Date	2015-09
Collateral	MOB	[2]
Principal and interest payments	Monthly/10-yr amort.	[3]
Principal and interest amortization period	10 years
Investment in Collateral	6,900,000
Mortgage notes payable carrying amount	4,200,000		4,300,000
Mortgage Notes 4.700% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	13,900,000	[1]
Effective Interest rate	4.70%	[1]
Maturity Date	2016-01	[1]
Collateral	MOB	[1],[2]
Principal and interest payments	Monthly/25-yr amort.	[1],[3]
Principal and interest amortization period	25 years	[1]
Investment in Collateral	26,400,000	[1]
Mortgage notes payable carrying amount	11,900,000	[1]	12,400,000	[1]
Unamortized portion of premium	300,000
Mortgage Notes 4.700% [Member] | Life Insurance Company - I [Member]
Debt Instrument [Line Items]
Mortgage notes	21,500,000	[12]
Effective Interest rate	4.70%	[1],[12]
Maturity Date	2015-08	[12]
Collateral	MOB	[12],[2]
Principal and interest payments	Monthly/25-yr amort.	[12],[3]
Principal and interest amortization period	25 years	[12]
Investment in Collateral	44,000,000	[12]
Mortgage notes payable carrying amount	18,100,000	[12]	18,800,000	[12]
Unamortized portion of premium	400,000
Mortgage Notes 5.100% [Member] | Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,300,000	[13]
Effective Interest rate	5.10%	[1],[13]
Maturity Date	2018-12	[13]
Collateral	MOB	[13],[2]
Principal and interest payments	Monthly/25-yr amort.	[13],[3]
Principal and interest amortization period	25 years	[13]
Investment in Collateral	14,600,000	[13]
Mortgage notes payable carrying amount	7,300,000	[13]	7,500,000	[13]
Unamortized portion of premium	600,000
Mortgage Notes 4.540% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	8,100,000	[14]
Effective Interest rate	4.54%	[1],[14]
Maturity Date	2016-08	[14]
Collateral	MOB	[14],[2]
Principal and interest payments	Monthly/10-yr amort.	[14],[3]
Principal and interest amortization period	10 years	[14]
Investment in Collateral	15,400,000	[14]
Mortgage notes payable carrying amount	7,800,000	[14]	7,700,000	[14]
Unamortized portion of premium	500,000
Mortgage Notes 4.060% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	5,300,000	[15],[16]
Effective Interest rate	4.06%	[1],[15],[16]
Maturity Date	2014-11	[15],[16]
Collateral	MOB	[15],[16],[2]
Principal and interest payments	Monthly/25-yr amort.	[15],[16],[3]
Principal and interest amortization period	25 years	[15],[16]
Investment in Collateral	11,600,000	[15],[16]
Mortgage notes payable carrying amount	4,500,000	[15],[16]	4,800,000	[15],[16]
Unamortized portion of premium	300,000
Number of buildings secured for mortgage note payable	2
Mortgage Notes 4.060% [Member] | Life Insurance Company - I [Member]
Debt Instrument [Line Items]
Mortgage notes	3,100,000	[17]
Effective Interest rate	4.06%	[1],[17]
Maturity Date	2014-11	[17]
Collateral	MOB	[17],[2]
Principal and interest payments	Monthly/25-yr amort.	[17],[3]
Principal and interest amortization period	25 years	[17]
Investment in Collateral	6,700,000	[17]
Mortgage notes payable carrying amount	2,600,000	[17]	2,800,000	[17]
Unamortized portion of premium	200,000
Mortgage Notes 4.000% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,900,000	[18]
Effective Interest rate	4.00%	[1],[18]
Collateral	MOB	[18],[2]
Principal and interest payments	Monthly/15-yr amort.	[18],[3]
Investment in Collateral	20,700,000	[18]
Mortgage notes payable carrying amount	5,100,000	[18]	0	[18]
Unamortized portion of premium	(300,000)
5.000%-7.625% Mortgage Notes Payable [Member]
Debt Instrument [Line Items]
Mortgage notes	225,242,000		225,377,000
Investment in Collateral	474,900,000
Mortgage notes payable carrying amount	222,500,000		221,649,000
Unaccreted discount	$ 2,755,000		$ 3,728,000
Contractual Interest Rates [Member]
Debt Instrument [Line Items]
Number of outstanding mortgage notes	20
Contractual interest rates, minimum	5.00%
Contractual interest rates, maximum	7.625%

[1] The unamortized portion of a $0.3 million premium recorded on this note upon acquisition is included in the balance above.

[2] The contractual interest rates for the twenty outstanding mortgage notes ranged from 5.0% to 7.625% as of December 31, 2012.

[3] Payable in monthly installments of principal and interest with the final payment due at maturity (unless otherwise noted).

[4] The unaccreted portion of a $2.7 million discount recorded on this note upon acquisition is included in the balance above.

[5] The unaccreted portion of a $2.1 million discount recorded on this note upon acquisition is included in the balance above.

[6] The unaccreted portion of a $2.4 million discount recorded on this note upon acquisition is included in the balance above.

[7] The unaccreted portion of a $0.2 million discount recorded on this note upon acquisition is included in the balance above.

[8] The unaccreted portion of a $1.0 million discount recorded on this note upon acquisition is included in the balance above.

[9] The Company has the option to extend the maturity for two, one-year floating rate extension terms.

[10] The unamortized portion of a $0.5 million premium recorded on this note upon acquisition is included in the balance above.

[11] The Company repaid this mortgage note payable on February 14, 2013.

[12] The unamortized portion of a $0.4 million premium recorded on this note upon acquisition is included in the balance above.

[13] The unamortized portion of the $0.6 million premium recorded on this note upon acquisition is included in the balance above.

[14] The unamortized portion of the $0.5 million premium recorded on this note upon acquisition is included in the balance above.

[15] Balance consists of two notes secured by the same building.

[16] The unamortized portions of the $0.3 million premium recorded on these notes upon acquisition are included in the balance above.

[17] The unamortized portion of the $0.2 million premium recorded on this note upon acquisition is included in the balance above.

[18] MOB-Medical office building; OTH-Other.