Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current
Federal									$ 19,804,000	$ 13,163,000	$ 21,040,000
State									3,243,000	2,732,000	4,427,000
Foreign									3,926,000	3,920,000	4,582,000
Deferred
Federal									3,646,000	(544,000)	(574,000)
State									404,000	(98,000)	(358,000)
Foreign									(430,000)	830,000	(1,231,000)
Income tax expense (benefit)	4,289,000	10,870,000	11,177,000	4,256,000	(6,785,000)	9,069,000	11,347,000	6,372,000	30,593,000	20,003,000	27,886,000
Income and loss from continuing operations before income taxes
Domestic									74,912,000	65,705,000	68,961,000
Foreign									6,652,000	(3,784,000)	9,825,000
Income before taxes	11,957,000	30,876,000	29,679,000	9,051,000	(902,000)	22,045,000	27,206,000	13,573,000	81,564,000	61,921,000	78,786,000
Reconciliations between the statutory federal income tax rates and effective income tax rates
Federal tax rate (as a percent)									35.00%	35.00%	35.00%
State taxes, net of federal benefit (as a percent)									3.00%	2.90%	3.40%
Tax benefit of domestic manufacturing deduction (as a percent)									(2.20%)	(2.10%)	(2.50%)
Change in valuation allowance (as a percent)									1.30%	6.00%	(0.30%)
Difference between United States statutory and foreign local tax rates (as a percent)									0.10%	2.60%	0.30%
Change in uncertain tax position (as a percent)									(0.40%)	(0.30%)
Worthless stock deduction on Irish subsidiary										(15.40%)
Non-deductible goodwill write-off										1.10%
Non-deductible professional fee										1.30%
Other (as a percent)									0.70%	1.20%	(0.50%)
Effective income tax rate (as a percent)									37.50%	32.30%	35.40%
Additional disclosures
Tax benefit from worthless stock deduction										$ 9,900,000