Stock-based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) item $ / shares shares	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares
Stock-based Compensation
Unrecognized compensation cost	$ 27,000			$ 27,000
Equity Incentive Plan 2010
Stock-based Compensation
Number of shares authorized | shares	5,768,763			5,768,763
Shares included in the authorized shares which was previously reserved for issuance | shares	768,763			768,763
Employee and Directors Stock Options
Stock-based Compensation
Term of award				10 years
Vesting period				3 years
Stock-based compensation	$ 0	$ 0
Unrecognized compensation cost	$ 0			$ 0
Shares
Balance at the beginning of the period (in shares) | shares				3,308,158
Exercised (in shares) | shares				(70,000)
Balance at the end of the period (in shares) | shares	3,238,158	3,308,158		3,238,158		3,308,158
Vested and exercisable at the end of the period (in shares) | shares	3,238,158			3,238,158
Exercise Price
Balance at the beginning of the period (in dollars per share) | $ / shares				$ 20.40
Exercised (in dollars per share) | $ / shares				23.77
Balance at the end of the period (in dollars per share) | $ / shares	$ 20.33	$ 20.40		20.33		$ 20.40
Vested and exercisable at the end of the period (in dollars per share) | $ / shares	$ 20.33			$ 20.33
Remaining Contractual Term
Remaining Contractual Term (in years)				2 years 11 months 27 days		3 years 6 months
Vested and exercisable				2 years 11 months 27 days
Aggregate Intrinsic Value
Balance at the beginning of the period				$ 46,086
Exercised				1,036
Balance at the end of the period	$ 55,158	$ 46,086		55,158		$ 46,086
Vested and exercisable at the end of the period	55,158			$ 55,158
Restricted Stock Units
Stock-based Compensation
Number of different vesting criteria | item				4
Stock-based compensation	$ 5,300		$ 4,500	$ 9,100	$ 7,700
Restricted Stock Units | Vesting Tranche One
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units | Vesting Tranche Three
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units | Vesting Tranche Four
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units | Minimum | Vesting Tranche Two
Stock-based Compensation
Vesting period				1 year
Restricted Stock Units | Maximum | Vesting Tranche Two
Stock-based Compensation
Vesting period				2 years
Restricted Stock With Total Shareholder Return Conditions | Minimum
Stock-based Compensation
Percentage of shares vested				0.00%
Restricted Stock With Total Shareholder Return Conditions | Maximum
Stock-based Compensation
Percentage of shares vested				200.00%