Stock-Based Compensation (Details 3) - Nonvested shares	6 Months Ended
	Jun. 30, 2016
Compounded Annual Book Value Per Share Growth 13%
Stock-based compensation
Compounded Annual Book Value Per Share Growth (as a percent)	13.00%
Nonvested Common Shares Earned (as a percent)	25.00%
Compounded Annual Book Value Per Share Growth 13% | Maximum
Stock-based compensation
Compounded Annual Book Value Per Share Growth (as a percent)	13.00%
Nonvested Common Shares Earned (as a percent)	0.00%
Compounded Annual Book Value Per Share Growth 14%
Stock-based compensation
Compounded Annual Book Value Per Share Growth (as a percent)	14.00%
Nonvested Common Shares Earned (as a percent)	50.00%
Compounded Annual Book Value Per Share Growth 15%
Stock-based compensation
Compounded Annual Book Value Per Share Growth (as a percent)	15.00%
Nonvested Common Shares Earned (as a percent)	75.00%
Compounded Annual Book Value Per Share Growth 16% | Minimum
Stock-based compensation
Compounded Annual Book Value Per Share Growth (as a percent)	16.00%
Nonvested Common Shares Earned (as a percent)	100.00%