Stock-Based Compensation Plans (Details 3) $ in Thousands		12 Months Ended
	Jan. 01, 2014 item	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Oct. 31, 1996 shares
Additional disclosures
Stock-based compensation expense		$ 14,666	$ 14,703	$ 13,314
Capitalized stock-based compensation cost		$ 9,266	9,667	5,457
Employee Stock Purchase Plan [Abstract]
Shares issued under Employee Stock Purchase Plan | shares		11,348
Stock-based compensation expense		$ 14,666	14,703	13,314
Stock Options
Additional disclosures
Forfeiture rate (as a percent)		0.80%
Performance awards
Additional disclosures
Maximum Measurement Period (in years)		3 years
Award vesting period (in years)		3 years
Performance awards | Maximum
Additional disclosures
Percentage of stock based compensation elected to be received in the form of stock options upon the election of the recipient		25.00%
Restricted Stock and Restricted Stock Units [Member]
Additional disclosures
Unrecognized compensation cost for unvested stock options		$ 24,421
Weighted average period for recognition of unrecognized compensation cost		3 years 6 months
Non Qualified Employee Stock Purchase Plan [Member]
Additional disclosures
Stock-based compensation expense		$ 289	$ 321	$ 407
Employee Stock Purchase Plan [Abstract]
Employee stock purchase plan, shares of common stock reserved for issuance | shares					1,000,000
Employee stock purchase plan, remaining shares of common stock available for issuance | shares		692,812
Employment period of full-time employees for becoming eligible to participate in the plan (in months)		1 month
Employment period of other employees for becoming eligible to participate in the plan (in months)		12 months
Number of purchase periods | item	2
Employee stock purchase plan, discounted stock price percentage		85.00%
Shares issued under Employee Stock Purchase Plan | shares		11,348	10,667	9,848
Stock-based compensation expense		$ 289	$ 321	$ 407