Property, Plant and Equipment

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

A summary of property, plant and equipment is shown below (in thousands):

	Estimated Life	December 31, 2014			December 31, 2013
	(in years)
Land	—	$	34,932		$	35,585
Buildings	40	199,159			191,348
Central office equipment	7 – 10	604,621			559,304
Outside communications plant	15 – 35	1,124,865			1,091,238
Furniture, vehicles and other work equipment	5 – 15	224,728			197,439
Plant under construction	—	90,979			93,734
Other	—	19,860			18,881
Total property, plant and equipment		2,299,144			2,187,529
Less: Accumulated depreciation		(1,085,415		)	(886,237		)
Net property, plant and equipment		$	1,213,729		$	1,301,292

Depreciation expense, excluding amortization of intangible assets, for the years ended December 31, 2014, 2013 and 2012 was $209.7 million, $271.3 million and $365.5 million, respectively. Depreciation expense includes amortization of assets recorded under capital leases.

The Company recorded a negligible amount of asset retirement obligations during the year ended December 31, 2014. Accretion expense, revisions in cash flow estimates and liability settlements were insignificant during the year. The Company's asset retirement obligations are included as a component of other accrued liabilities or other long-term liabilities in the consolidated balance sheets based on the expected timing of the obligation. As of December 31, 2014, the Company's asset retirement liability of $4.4 million consisted of $1.1 million in other accrued liabilities and $3.3 million in other long-term liabilities. As of December 31, 2013, the Company's asset retirement liability of $4.3 million consisted of $1.1 million in other accrued liabilities and $3.2 million in other long-term liabilities.