Commitments and Contingencies (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]
Rental expense for operating leases	$ 2,400,000	$ 2,400,000	$ 4,900,000	$ 4,600,000
Defined benefit plan employer matching contribution on first five percent of employee compensation			50.00%
Percentage of employees' eligible compensation for employer matching contribution			5.00%
Defined benefit plan employer contribution limit			$ 6,000
Defined benefit plan employer contribution vesting period			5 years
Defined benefit plan employer contribution	$ 400,000	$ 300,000	$ 800,000	$ 600,000