Notes and Bonds Payable - Details of Mortgage Notes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 mortgage_note_payable		Dec. 31, 2013
Debt Instrument [Line Items]
Number of outstanding mortgage notes	17
Mortgage notes payable [Member]
Debt Instrument [Line Items]
Investment in Collateral	$ 402,100,000	[1]
Mortgage notes payable carrying amount	173,300,000		165,800,000
Number of outstanding mortgage notes	22
Contractual interest rates, minimum	5.00%
Contractual interest rates, maximum	7.60%
Mortgage notes payable [Member] | Mortgage Notes 7.765% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	4,700,000
Effective Interest rate	7.77%	[2]
Maturity Date	2017-01
Collateral	MOB	[3]
Principal and interest payments	Monthly/20-yr amort.	[4]
Principal and interest amortization period	20 years
Investment in Collateral	12,100,000
Mortgage notes payable carrying amount	900,000		1,200,000
Mortgage notes payable [Member] | Mortgage Notes 5.550% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	1,800,000
Effective Interest rate	5.55%	[2]
Maturity Date	2030-10
Collateral	OTH	[3]
Principal and interest payments	Monthly/27-yr amort.	[4]
Principal and interest amortization period	27 years
Investment in Collateral	7,900,000
Mortgage notes payable carrying amount	1,500,000		1,500,000
Mortgage notes payable [Member] | Mortgage Notes 5.490% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	15,100,000
Effective Interest rate	5.49%	[2]
Maturity Date	2016-01
Collateral	MOB	[3]
Principal and interest payments	Monthly/10-yr amort.	[4]
Principal and interest amortization period	10 years
Investment in Collateral	36,100,000
Mortgage notes payable carrying amount	11,900,000		12,300,000
Mortgage notes payable [Member] | Mortgage Notes 6.480% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	17,400,000	[5]
Effective Interest rate	6.48%	[2],[5]
Maturity Date	2015-05	[5]
Collateral	MOB	[3],[5]
Principal and interest payments	Monthly/10-yr amort.	[4],[5]
Principal and interest amortization period	10 years	[5]
Investment in Collateral	20,200,000	[5]
Mortgage notes payable carrying amount	14,800,000	[5]	14,700,000	[5]
Unaccreted discount	2,700,000
Mortgage notes payable [Member] | Mortgage Notes 6.110% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	12,000,000	[6]
Effective Interest rate	6.11%	[2],[6]
Maturity Date	2015-07	[6]
Collateral	2 MOBs	[3],[6]
Principal and interest payments	Monthly/10-yr amort.	[4],[6]
Principal and interest amortization period	10 years	[6]
Investment in Collateral	19,400,000	[6]
Mortgage notes payable carrying amount	10,100,000	[6]	10,000,000	[6]
Unaccreted discount	2,100,000
Mortgage notes payable [Member] | Mortgage Notes 7.650% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	15,200,000	[7],[8]
Effective Interest rate	7.65%	[2],[7],[8]
Maturity Date	2020-07	[8]
Collateral	MOB	[3],[7],[8]
Principal and interest amortization period	11 years
Investment in Collateral	20,200,000	[7],[8]
Mortgage notes payable carrying amount	12,700,000	[7],[8]	12,700,000	[7],[8]
Unaccreted discount	2,400,000	[7],[8]
Period for monthly installments of interest	24 months
Mortgage notes payable [Member] | Mortgage Notes 6.430% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	12,900,000	[9]
Effective Interest rate	6.43%	[2],[9]
Maturity Date	2021-02	[9]
Collateral	MOB	[3],[9]
Principal and interest payments	Monthly/12-yr amort.	[4],[9]
Principal and interest amortization period	12 years	[9]
Investment in Collateral	20,700,000	[9]
Mortgage notes payable carrying amount	11,000,000	[9]	11,100,000	[9]
Unaccreted discount	1,000,000	[9]
Mortgage notes payable [Member] | Mortgage Notes 5.530% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,000,000
Effective Interest rate	5.53%	[2]
Maturity Date	2018-01
Collateral	MOB	[3]
Principal and interest payments	Monthly/15-yr amort.	[4]
Principal and interest amortization period	15 years
Investment in Collateral	14,900,000
Mortgage notes payable carrying amount	1,900,000		2,500,000
Mortgage notes payable [Member] | Mortgage Notes 5.250% [Member] | Investment Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	4,600,000
Effective Interest rate	5.25%	[2]
Maturity Date	2015-09
Collateral	MOB	[3]
Principal and interest payments	Monthly/10-yr amort.	[4]
Principal and interest amortization period	10 years
Investment in Collateral	6,500,000
Mortgage notes payable carrying amount	4,100,000		4,200,000
Mortgage notes payable [Member] | Mortgage Notes 4.700% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	13,900,000	[10]
Effective Interest rate	4.70%	[10],[2]
Maturity Date	2016-01	[10]
Collateral	MOB	[10],[3]
Principal and interest payments	Monthly/25-yr amort.	[10],[4]
Principal and interest amortization period	25 years	[10]
Investment in Collateral	26,700,000	[10]
Mortgage notes payable carrying amount	11,000,000	[10]	11,500,000	[10]
Unamortized premium	300,000	[10]
Mortgage notes payable [Member] | Mortgage Notes 4.700% [Member] | Life Insurance Company - I [Member]
Debt Instrument [Line Items]
Mortgage notes	21,500,000	[11]
Effective Interest rate	4.70%	[11],[2]
Maturity Date	2015-08	[11]
Collateral	MOB	[11],[3]
Principal and interest payments	Monthly/25-yr amort.	[11],[4]
Principal and interest amortization period	25 years	[11]
Investment in Collateral	41,500,000	[11]
Mortgage notes payable carrying amount	16,600,000	[11]	17,400,000	[11]
Unamortized premium	400,000	[11]
Mortgage notes payable [Member] | Mortgage Notes 5.100% [Member] | Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,300,000	[12]
Effective Interest rate	5.10%	[12],[2]
Maturity Date	2018-12	[12]
Collateral	MOB	[12],[3]
Principal and interest payments	Monthly/25-yr amort.	[12],[4]
Principal and interest amortization period	25 years	[12]
Investment in Collateral	13,700,000	[12]
Mortgage notes payable carrying amount	6,800,000	[12]	7,000,000	[12]
Unamortized premium	600,000	[12]
Mortgage notes payable [Member] | Mortgage Notes 4.540% [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	8,100,000	[13]
Effective Interest rate	4.54%	[13],[2]
Maturity Date	2016-08	[13]
Collateral	MOB	[13],[3]
Principal and interest payments	Monthly/10-yr amort.	[13],[4]
Principal and interest amortization period	10 years	[13]
Investment in Collateral	15,700,000	[13]
Mortgage notes payable carrying amount	7,500,000	[13]	7,600,000	[13]
Unamortized premium	500,000	[13]
Mortgage notes payable [Member] | Mortgage Notes 4.060% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	5,300,000	[14]
Effective Interest rate	4.06%	[14],[2]
Maturity Date	2014-11	[14]
Collateral	MOB	[14],[3]
Principal and interest payments	Monthly/25-yr amort.	[14],[4]
Principal and interest amortization period	25 years	[14]
Investment in Collateral	0	[14]
Mortgage notes payable carrying amount	0	[14]	4,300,000	[14]
Number of buildings secured for mortgage note payable	2	[14]
Mortgage notes payable [Member] | Mortgage Notes 4.060% [Member] | Life Insurance Company - I [Member]
Debt Instrument [Line Items]
Mortgage notes	3,100,000	[15]
Effective Interest rate	4.06%	[15],[2]
Maturity Date	2014-11	[15]
Collateral	MOB	[15],[3]
Principal and interest payments	Monthly/25-yr amort.	[15],[4]
Principal and interest amortization period	25 years	[15]
Investment in Collateral	0	[15]
Mortgage notes payable carrying amount	0	[15]	2,500,000	[15]
Mortgage notes payable [Member] | Mortgage Notes 4.000% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,900,000	[16]
Effective Interest rate	4.00%	[16],[2]
Maturity Date	2020-08	[16]
Collateral	MOB	[16],[3]
Principal and interest payments	Monthly/15-yr amort.	[16],[4]
Principal and interest amortization period	15 years	[16]
Investment in Collateral	20,700,000	[16]
Mortgage notes payable carrying amount	4,000,000	[16]	4,600,000	[16]
Unamortized premium	300,000	[16]
Mortgage notes payable [Member] | Mortgage Notes 5.25% 20 Year [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	15,000,000	[17]
Effective Interest rate	5.25%	[17],[2]
Maturity Date	2027-04	[17]
Collateral	MOB	[17],[3]
Principal and interest payments	Monthly/20-yr amort	[17],[4]
Principal and interest amortization period	20 years	[17]
Investment in Collateral	33,400,000	[17]
Mortgage notes payable carrying amount	11,900,000	[17]	12,500,000	[17]
Unamortized premium	700,000	[17]
Mortgage notes payable [Member] | Mortgage Notes 5% Thirty Year [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	18,300,000	[13]
Effective Interest rate	5.00%	[13],[2]
Maturity Date	2016-12	[13]
Collateral	MOB	[13],[3]
Principal and interest payments	Monthly/30-yr amort	[13],[4]
Principal and interest amortization period	30 years	[13]
Investment in Collateral	33,600,000	[13]
Mortgage notes payable carrying amount	16,500,000	[13]	17,000,000	[13]
Unamortized premium	500,000	[13]
Mortgage notes payable [Member] | Mortgage Notes 5% 25 Year [Member] | Commercial Bank [Member]
Debt Instrument [Line Items]
Mortgage notes	13,100,000	[1]
Effective Interest rate	5.00%	[1],[2]
Maturity Date	2016-04	[1]
Collateral	MOB	[1],[3]
Principal and interest payments	Monthly/25-yr amort	[1],[4]
Principal and interest amortization period	25 years	[1]
Investment in Collateral	20,100,000	[1]
Mortgage notes payable carrying amount	10,700,000	[1]	11,200,000	[1]
Unamortized premium	200,000	[1]
Mortgage notes payable [Member] | Mortgage Notes 4.860% [Member] | Life Insurance Co. [Member]
Debt Instrument [Line Items]
Mortgage notes	7,300,000	[18]
Effective Interest rate	4.86%	[18],[2]
Maturity Date	2020-08	[18]
Collateral	MOB	[18],[3]
Principal and interest payments	Monthly/27-yr amort	[18],[4]
Principal and interest amortization period	27 years	[18]
Investment in Collateral	17,800,000	[18]
Mortgage notes payable carrying amount	7,100,000	[18]	0	[18]
Unamortized premium	400,000	[18]
Mortgage notes payable [Member] | Mortgage Notes 4.790% [Member] | Municipal Government [Member]
Debt Instrument [Line Items]
Mortgage notes	11,900,000	[19],[20]
Effective Interest rate	4.79%	[19],[2],[20]
Collateral	MOB	[19],[20],[3]
Principal and interest payments	Semi-Annual (18)	[19],[20],[4]
Investment in Collateral	20,900,000	[19],[20]
Mortgage notes payable carrying amount	12,300,000	[19],[20]	0	[19],[20]
Unamortized premium	$ 1,000,000	[19],[20]
Number of buildings secured for mortgage note payable	4	[19],[20]
Number of outstanding mortgage notes	4

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

[2] The contractual interest rates for the 22 outstanding mortgage notes ranged from 5.0% to 7.6% as of December 31, 2014.

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

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

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

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

[7] Payable in monthly installments of interest only for 24 months and then installments of principal and interest based on an 11-year amortization with the final payment due at maturity.

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

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

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

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

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

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

[14] Balance consists of two notes secured by the same building. The company repaid these notes in October 2014.

[15] The company repaid this mortgage note in October 2014.

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

[17] The unamortized portion of the $0.7 million premium recorded on this note upon acquisition is included in the balance above.

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

[19] The unamortized portion of the $1.0 million premium recorded on the four notes upon acquisition is included in the balance above.

[20] Balance consists of four notes secured by the same building.