Employee Benefit Plans - Additional Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plan [Line Items]
Long term portions of pension plan liabilities	$ 6,037,000	$ 2,322,000
Defined benefit plan contributions by employer	2,600,000	1,700,000	1,300,000
Global Equities
Employee Benefit Plan [Line Items]
Defined benefit plan, target plan asset allocations	60.00%
Global Bonds
Employee Benefit Plan [Line Items]
Defined benefit plan, target plan asset allocations	23.00%
Alternative Assets
Employee Benefit Plan [Line Items]
Defined benefit plan, target plan asset allocations	7.00%
Cash
Employee Benefit Plan [Line Items]
Defined benefit plan, target plan asset allocations	10.00%
Funded Status
Employee Benefit Plan [Line Items]
Current portions of pension plan liabilities	100,000
Long term portions of pension plan liabilities	6,000,000
Pension Plan
Employee Benefit Plan [Line Items]
Accrued retirement allowance amount transfer period	4 years
UNITED KINGDOM
Employee Benefit Plan [Line Items]
Funding valuation period	3 years
Defined benefit plan contributions by employer	1,000,000	847,000
Defined benefit plan estimated employer contributions for 2014	1,000,000
JAPAN
Employee Benefit Plan [Line Items]
Defined benefit plan contributions by employer	253,000	521,000
Defined benefit plan estimated employer contributions for 2014	$ 100,000