4. Acquired Intangible Assets and Liabilities

Summarized below are the carrying values for the major classes of intangible assets and liabilities (in thousands):


		December 31, 2017						December 31, 2016
	Useful Lives	Gross Carrying Value		Accumulated Amortization		Net Carrying Value		Gross Carrying Value		Accumulated Amortization		Net Carrying Value
Customer Relationships	1 to 12 years	$	95,705	$	(20,512)	$	75,193	$	95,705	$	(12,358)	$	83,347
In-Place Leases	0.5 to 10 years		32,066		(12,987)		19,079		32,066		(7,197)		24,869
Solar Power Agreement (1)	17 years		13,747		(2,830)		10,917		13,747		(2,022)		11,725
Platform Intangible	3 years		9,600		(8,133)		1,467		9,600		(4,933)		4,667
Acquired Favorable Leases	0.5 to 8 years		4,649		(2,328)		2,321		4,652		(1,013)		3,639
Tradenames	3 years		3,100		(2,626)		474		3,100		(1,593)		1,507
Total Intangible Assets		$	158,867	$	(49,416)	$	109,451	$	158,870	$	(29,116)	$	129,754

Solar Power Agreement (1)	17 years		13,747		(2,830)		10,917		13,747		(2,022)		11,725
Acquired Unfavorable Leases
Acquired below market leases - as Lessor	3 to 4 years		809		(375)		434		809		(138)		671
Acquired above market leases - as Lessee	11 to 12 years		2,453		(550)		1,903		2,453		(334)		2,119
Total Intangible Liabilities (2)		$	17,009	$	(3,755)	$	13,254	$	17,009	$	(2,494)	$	14,515

(1)

Amortization related to the Solar Power Agreement asset and liability is recorded at the same rate and therefore has no net impact on the statement of operations.

(2)

Intangible liabilities are included within the “Advance rents, security deposits and other liabilities” line item of the consolidated balance sheets.

Above or below market leases are amortized as a reduction to or increase in rental revenue as well as a reduction to rent expense in the case of the Company as lessee over the remaining lease terms. The net effect of amortization of acquired above‑market and below‑market leases resulted in a net decrease in rental revenue of $0.9 million and $0.7 million for the years ended December 31, 2017 and 2016, respectively, as well as a decrease in rental expense of $0.1 million for the year ended December 31, 2015. The estimated amortization of acquired favorable and unfavorable leases for each of the five succeeding fiscal years ending December 31 is as follows (in thousands):


	Net Rental Revenue Decreases		Rental Expense Decreases
2018	$	681	$	216
2019		479		216
2020		647		216
2021		46		216
2022		17		216
Thereafter		17		823
Total	$	1,887	$	1,903

Net amortization of all other identified intangible assets and liabilities was $18.2 million, $19.0 million and $9.0 million for the years ended December 31, 2017, 2016 and 2015, respectively. The estimated net amortization of all other identified intangible assets and liabilities for each of the five succeeding fiscal years ending December 31 is as follows (in thousands):


2018	$	14,574
2019		11,965
2020		11,379
2021		10,137
2022		9,910
Thereafter		38,248
Total	$	96,213