Public Offering (Detail Textuals) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	6 Months Ended
	Jun. 30, 2014	Jul. 31, 2014
Stockholders Equity Note [Line Items]
Common stock shares sold during the period	1,725,000
Net proceeds from the offering after payment of underwriting discounts and expenses of the offering	$ 128,700	$ 128,686
Underwriters' option
Stockholders Equity Note [Line Items]
Common stock shares sold during the period	225,000
Public offering price per share	$ 77.63