Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 19,132	$ 23,528	$ 25,603	$ 21,512
Income tax expense using estimated annual effective income tax rate	6,279	9,575	8,404	8,755
Changes in effective tax rates	(178)	321	0	0
Impact of discrete items, net	0	121	639	927
Income tax expense	$ 6,101	$ 10,017	$ 9,043	$ 9,682