Goodwill and Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2013

Changes to goodwill are as follows:



(in thousands)	Nine Months Ended September 30, 2013			Year Ended December 31, 2012
Balance at beginning of period	$	813,792		$	820,824
Disposals	—			(13,966		)
Currency translation	(2,518		)	6,934
Balance at end of period	$	811,274		$	813,792

Changes to intangible assets are as follows:



(in thousands)	Nine Months Ended September 30, 2013			Year Ended December 31, 2012
Balance at beginning of period, net of accumulated amortization	$	125,913		$	146,227
Disposals	—			(3,789		)
Amortization expense	(12,290		)	(16,907		)
Currency translation and other	1,168			382
Balance at end of period, net of accumulated amortization	$	114,791		$	125,913

A summary of intangible assets follows:



	Weighted Average Amortization Period of Finite Lived Assets (in years)
		September 30, 2013						December 31, 2012
(dollars in thousands)		Gross Asset		Accumulated Amortization		Net		Gross Asset		Accumulated Amortization		Net
Intellectual property rights	18.8	$	88,950	$	49,105	$	39,845	$	88,614	$	47,202	$	41,412
Customer relationships and backlog	11.7	139,774		81,092		58,682		140,250		73,630		66,620
Drawings	37.9	11,149		9,925		1,224		11,149		9,850		1,299
Other	14.0	51,179		36,139		15,040		51,093		34,511		16,582
Total	14.1	$	291,052	$	176,261	$	114,791	$	291,106	$	165,193	$	125,913

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.