Related Party Transactions and Arrangements (Merger Related Costs) (Narrative) (Details) - USD ($)		12 Months Ended
	Jan. 08, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Related party expenses			$ 8,500,000
Affiliates of Former Manager [Member]
Related Party Transaction [Line Items]
Related party expenses			8,500,000
Affiliates of Former Manager [Member] | Acquisition Related Expenses [Member]
Related Party Transaction [Line Items]
Percentage of contract purchase price				1.00%
Affiliates of Former Manager [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Payments of related party expenses		$ 0
Affiliated Entity [Member] | Acquisition Related Expenses [Member]
Related Party Transaction [Line Items]
Related party expenses		0	1,652,000	$ 37,564,000
Affiliated Entity [Member] | Merger And Acquisition Related Costs [Member]
Related Party Transaction [Line Items]
Related party expenses		$ 0
Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses			27,265,000	36,096,000
ARCT III [Member] | Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses				0
ARCT IV [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				$ 7,700,000
Percentage of transaction value				0.25%
ARCT IV [Member] | Strategic and Financial Services Fee Reimbursement [Member]
Related Party Transaction [Line Items]
Related party expenses				$ 800,000
ARCT IV [Member] | Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses			8,400,000	16,075,000
Cole Merger [Member] | Affiliates of Former Manager [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Related party expenses			$ 14,200,000	14,200,000
Percentage of contract purchase price			0.25%
Cole Merger [Member] | Affiliated Entity [Member] | Transaction Management Support [Member]
Related Party Transaction [Line Items]
Related party expenses	$ 2,900,000
Cole Merger [Member] | Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses			$ 17,115,000	14,215,000
CapLease Merger [Member] | Affiliates of Former Manager [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				$ 5,600,000
Percentage of contract purchase price				0.25%
CapLease Merger [Member] | Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses				$ 5,563,000
Multiple-tenant Spin-off [Member] | Affiliated Entity [Member] | Strategic Advisory Services [Member]
Related Party Transaction [Line Items]
Related party expenses			1,750,000
ARC Advisory [Member] | ARCT III [Member] | Affiliated Entity [Member] | Acquisition Expense Reimbursements [Member]
Related Party Transaction [Line Items]
Related party expenses				300,000
ARC Advisory [Member] | CapLease Merger [Member] | Affiliates of Former Manager [Member] | Strategic and Financial Services Fee Reimbursement [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				200,000
RCS Advisory [Member] | ARCT III [Member] | Affiliated Entity [Member] | Acquisition Expense Reimbursements [Member]
Related Party Transaction [Line Items]
Related party expenses				400,000
RCS Advisory [Member] | ARCT IV [Member] | Acquisition Expense Reimbursements [Member]
Related Party Transaction [Line Items]
Related party expenses				600,000
Payments of related party expenses				500,000
RCS Advisory [Member] | ARCT IV [Member] | Acquisition Related Expenses [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				600,000
RCS Advisory [Member] | ARCT IV [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Payments of related party expenses			$ 8,400,000	$ 7,700,000
Percentage of transaction value				0.25%
RCS Advisory [Member] | CapLease Merger [Member] | Affiliates of Former Manager [Member] | Strategic and Financial Services Fee Reimbursement [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				$ 3,600,000
RCS, RCS Advisory, and ANST [Member] | ARCT IV [Member] | Strategic and Financial Advisory Services Fee [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				800,000
RCS, RCS Advisory, and ANST [Member] | ARCT IV [Member] | Strategic and Financial Services Fee Reimbursement [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				200,000
RCS Advisory and ARC Advisory [Member] | ARCT IV [Member] | Merger And Acquisition Related Costs [Member]
Related Party Transaction [Line Items]
Payments of related party expenses				$ 500,000