Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2016

Equity incentive plans

Summary of stock option activity

        The following table summarizes stock option activity for the years ended December 31, 2016, 2015 and 2014(shares and intrinsic values in thousands):

	Number of shares			Weighted- average exercise price		Weighted- average remaining contractual term		Aggregate intrinsic value
Outstanding at December 31, 2013		1,730		$	11.20		9.3	$	2,208
Granted		140		$	11.56		9.7		—
Exercised		—			—		—		—
Forfeited or expired		—			—		—		—
Outstanding at December 31, 2014		1,870		$	11.23		8.4	$	4,721
Granted		215		$	13.61		6.2		—
Exercised		(15	)		10.60		—		—
Forfeited or expired		(27	)		10.60		—		—
Outstanding at December 31, 2015		2,043		$	11.49		7.6	$	6,740
Granted		890		$	11.97		6.2		—
Exercised		(13	)		10.60		—		—
Forfeited or expired		—			—		—		—
Outstanding at December 31, 2016		2,920		$	11.64		7.6	$	1,274
Vested at December 31, 2016		1,533		$	11.55		6.5	$	974
Exercisable at December 31, 2016		1,533		$	11.55		6.5	$	974

Summary of restricted share activity

        The following table summarizes restricted share activity for the years ended December 31, 2016, 2015 and 2014 (shares in thousands):

	Number of shares			Weighted-average grant date fair value
Outstanding at December 31, 2013		945		$	10.18
Granted		79			11.34
Vested		(305	)		11.33
Forfeited		—			—
Outstanding at December 31, 2014		719		$	9.82
Granted		99		$	12.42
Vested		(324	)		10.65
Forfeited		—			—
Outstanding at December 31, 2015		494		$	9.79
Granted		395			11.82
Vested		(328	)		10.88
Forfeited		—			—
Outstanding at December 31, 2016		561		$	10.58

Time Based Stock Option | Black Scholes Pricing Model

Equity incentive plans

Schedule of valuation assumptions

Black-Scholes Option Valuation Assumptions	2016	2015	2014
Risk-free interest rate	1.60% - 2.44%	1.76% - 2.12%	1.76% - 1.92%
Dividend yield	—	—	—
Volatility	26.4% - 32.4%	25.8% - 29.5%	28.4% - 30.9%
Weighted-average expected term (years)	6.2	6.3	6.0 - 6.3