Acquisitions (Fiscal Year 2012 Acquisitions) (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended		3 Months Ended								12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended
	Nov. 26, 2014	Apr. 02, 2014	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 03, 2012	Dec. 31, 2011	Apr. 05, 2012	Apr. 10, 2012	Apr. 17, 2012	Apr. 17, 2012	May 23, 2012	Jul. 23, 2012	Oct. 02, 2012	Oct. 09, 2012
Business Acquisition [Line Items]
Date of acquisition											Dec. 17, 2014
Fair value of the consideration paid		$ 69,026
Cash paid for business acquisition	54,552	51,526
Value of shares paid for acquisition		17,500
Revenue			187,438	166,944	151,512	147,758	154,817	135,717	120,787	102,079	653,652	513,400	353,633
Operating income (loss)			4,228	8,208	4,362	9,517	17,976	28,570	16,796	17,519	26,315	80,861	60,571
Initial Lease Term [Member]
Business Acquisition [Line Items]
Lease term											5 years
Successive Lease Term [Member]
Business Acquisition [Line Items]
Lease term											3 years
Number of successive lease terms											2
Z Corporation And Vidar Systems Corporation [Member]
Business Acquisition [Line Items]
Date of acquisition											Jan. 03, 2012
Business acquisition, ownership percentage														100.00%
Cash paid for business acquisition														134,918
Revenue													55,637
Operating income (loss)													8,478
Pro forma revenue													353,633		286,956
Pro forma net income (loss)													38,941		27,487
Fresh Fiber B.V. [Member]
Business Acquisition [Line Items]
Date of acquisition											Apr. 05, 2012
Business acquisition, ownership percentage																100.00%
Fair value of the consideration paid																1,243
Cash paid for business acquisition																848
Value of shares paid for acquisition																395
Time Period Of Earnout																3 years
Kodama Studios, LLC [Member]
Business Acquisition [Line Items]
Date of acquisition											Apr. 10, 2012
Business acquisition, ownership percentage																	100.00%
Fair value of the consideration paid																	2,749
Cash paid for business acquisition																	1,499
Value of shares paid for acquisition																	1,250
Paramount Industries [Member]
Business Acquisition [Line Items]
Date of acquisition											Apr. 17, 2012
Fair value of the consideration paid																			7,953
Cash paid for business acquisition																			6,138
Value of shares paid for acquisition																			1,815
Time Period Of Earnout																		5 years
Bespoke Innovations, Inc. [Member]
Business Acquisition [Line Items]
Date of acquisition											May 23, 2012
Business acquisition, ownership percentage																				100.00%
Fair value of the consideration paid																				7,903
Cash paid for business acquisition																				4,064
Value of shares paid for acquisition																				3,144
Maximum Deferred Payment Of Seller																				695
Viztu Technologies, Inc. [Member]
Business Acquisition [Line Items]
Date of acquisition											Jul. 23, 2012
Business acquisition, ownership percentage																					100.00%
Fair value of the consideration paid																					1,000
Cash paid for business acquisition																					500
Value of shares paid for acquisition																					500
Maximum Earnout Payment																					1
Business acquisition agreement, period																					4 years
TIM Innovative Modelmakers B.V. [Member]
Business Acquisition [Line Items]
Date of acquisition											Oct. 01, 2012
Business acquisition, ownership percentage																						100.00%
Fair value of the consideration paid																						1,714
Cash paid for business acquisition																						1,148
Value of shares paid for acquisition																						566
INUS Technology, Inc. [Member]
Business Acquisition [Line Items]
Date of acquisition											Oct. 09, 2012
Business acquisition, ownership percentage																							100.00%
Cash paid for business acquisition																							$ 33,918