Segment Reporting - Summary of Revenues, Gross Profit and Operating Income (Loss) by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 356,595	$ 350,138	$ 1,002,857	$ 979,240
Gross profit	77,121	63,939	208,364	196,920
Operating income (loss)	24,938	(13,934)	48,586	15,819
Reportable Geographical Components [Member] | United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	267,001	242,795	742,976	681,043
Gross profit	56,243	40,507	148,736	132,790
Operating income (loss)	11,464	(12,955)	19,188	604
Reportable Geographical Components [Member] | Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	45,340	55,742	131,391	139,817
Gross profit	9,998	13,893	30,677	32,889
Operating income (loss)	6,258	10,359	19,700	21,911
Reportable Geographical Components [Member] | Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	14,905	20,096	42,668	63,887
Gross profit	4,025	3,544	12,085	12,846
Operating income (loss)	570	(687)	2,511	692
Reportable Geographical Components [Member] | Other Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	29,349	31,505	85,822	94,493
Gross profit	6,855	5,995	16,866	18,395
Operating income (loss)	$ 6,646	$ (10,651)	$ 7,187	$ (7,388)