19.	Fixed Assets, Net

Fixed assets, net consisted of the following (in thousands):

	September 30, 2018			December 31, 2017
Computer and communications equipment	$	155,946		$	151,499
Software, including software development costs		201,119			164,011
Leasehold improvements and other fixed assets		200,485			179,178
		557,550			494,688
Less: accumulated depreciation and amortization		(341,419	)		(305,341	)
Fixed assets, net	$	216,131		$	189,347

Depreciation expense was $7.8 million and $7.5 million for the three months ended September 30, 2018 and 2017, respectively. Depreciation expense was $23.0 million and $22.9 million for the nine months ended September 30, 2018 and 2017, respectively. Depreciation is included as part of “Occupancy and equipment” in the Company’s unaudited condensed consolidated statements of operations.

The Company has approximately $7.5 million of asset retirement obligations related to certain of its leasehold improvements. The associated asset retirement cost is capitalized as part of the carrying amount of the long-lived asset. The liability is discounted and accretion expense is recognized using the credit adjusted risk-free interest rate in effect when the liability was initially recognized.

For the three months ended September 30, 2018 and 2017, software development costs totaling $14.4 million and $13.5 million, respectively, were capitalized. Amortization of software development costs totaled $7.5 million and $4.7 million for the three months ended September 30, 2018 and 2017. For the nine months ended September 30, 2018 and 2017, software development costs totaling $38.5 million and $27.8 million, respectively, were capitalized. Amortization of software development costs totaled $19.0 million and $15.3 million for the nine months ended September 30, 2018 and 2017, respectively. Amortization of software development costs is included as part of “Occupancy and equipment” in the Company’s unaudited condensed consolidated statements of operations.

Impairment charges of $0.7 million and $0.5 million were recorded for the three months ended September 30, 2018 and 2017, respectively, related to the evaluation of capitalized software projects for future benefit and for fixed assets no longer in service. Impairment charges of $0.7 million and $1.2 million were recorded for the nine months ended September 30, 2018 and 2017, respectively, related to the evaluation of capitalized software projects for future benefit and for fixed assets no longer in service. The impairment charges for the nine months ended September 30, 2018 and 2017 were related to the Financial Services segment. Impairment charges related to capitalized software and fixed assets are reflected in “Occupancy and equipment” in the Company’s unaudited condensed consolidated statements of operations.