Stockholders' Equity (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Treasury Stock, Shares, Acquired	141,358	180,822	493,890
Treasury Stock Acquired, Average Cost Per Share	$ 42.78	$ 46.46	$ 45.16
Stock Repurchase Program, Authorized Amount	$ 400,000,000
Stock Repurchased and Retired During Period, Shares	652,835
Stock Repurchased and Retired During Period, Value	$ 27,900,000
Stock Repurchase and Retired During Period, Weighted Average Price	$ 37.59
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 372,100,000
Capitalsource, Inc. [Member]
Proceeds from (Repurchase of) Equity		$ 58,000	$ (115,000)
Repurchased common stock from dividend reinvestment program		1,300	2,583